G Musulmanbekov

genisjinrru

On Hyperon Production and Polarization in HIC

Contentbull Motivationbull Strangeness Enhancement From subthreshold yield

of K+-s to lsquoHornrsquo-effect

bull New interpretation of Strangeness Enhancement bull Hyperon Polarization in HICbull Global Polarization of Hyperons

ndash Effects of Strong magnetic field in HICndash Effects of Angular Momentum and Vorticity in HIC

bull Conclusion

Which one of the following scenario is realized

Does a Phase Transition take place in central Heavy Ion Collisions (HIC)

Mixed Phase Critical Endpoint

B

Hadronic

matter

Critical

endpoint

Plasma

Nuclei

Chiral symmetry

broken

Chiral symmetry

restored

Colour

superconductor

Neutron stars

T

1st

order

line

Quark-

Gluon

Space-time Evolution of HIC

~ 10 fmc

Phase diagram ndash artistrsquos view

Phases of strongly interacting nuclear matter

L-G

Phase diagram with triple critical point

Space-time Evolution of HIC

expa

nsio

n

Space-time Evolution of HIC

eg

space

time

Hard Scattering

AuAu

Expan

sion

Hadron-Resonance

Gas

Freeze-out

jet JYg p ppK p L

p

What are we searching for

bull Signatures of phase transition andor mixed phase

bull QCD critical (triple)endpoint

bull Onset of chiral symmetry restoration at high ρB

bull The equation-of-state at high ρB

Observables

Signatures of phase transition andor mixed phase

bull excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

bull transverse mass spectra of kaon

bull particle correlations

QCD critical endpoint

bull excitation function of event-by-event fluctuations (multiplicities Kπ transverse momenta hellip)

Onset of chiral symmetry restoration at high ρB

bull dilepton yield (ρ ω φ rarr e+e-(μ+μ-))

The equation-of-state at high ρB

bull collective flow of hadrons

bull strange particle production at a threshold

bull PT in HIC is not stable state but transient onebull PT evolves in finite spacetime

There is not a crucial signal of PT

Every signal is essentially washed out due to subsequent interactions

Signatures of phase transition

andor mixed phase

Excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

Energy range radics = 2 ndash 11 GeV most interesting

bull Enhanced yield of K+

experiments KaoS at SIS AGS NA49

bull Horn Effect (irregular behaviour of K+

π+

)

bull Kink in Inverse Slope of Kaon pt Distributions

experiments NA49 STAR (BES RHIC program)

Enhanced yield of K+ in subthreshold kaon production

Transport models with NN-interactions

bull underestimate yield of K+

by a factor of 6

bull overestimate yield of K-

J Phys G Nucl Part Phys 27 (2001) 275

KaoS at SIS

RQMD

bull K+

N repulsive potential

bull K-

N attractive potential

bull Momentum dependent Skyrme forces

bull Compression parameter

soft ndash 200 MeV

hard ndash 380 MeV

Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios

100 101 102 103 104000

005

010

015

020

025 y=0

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K++

HSD UrQMD 13

100 101 102 103 104000

005

010

015

020

025 ltK+gtlt+

gt 4

E866 NA49

BRAHMS 5

HSD UrQMD 13

Elab

A [GeV]

100 101 102 103 104

000

005

010

015

020

025

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K

100 101 102 103 104

000

005

010

015

020

025

E866

NA49

BRAHMS 5

ltKgtltgt

100 101 102 103 104000

002

004

006

008

E877

NA49 STAR

(+0)

100 101 102 103 104000

002

004

006

008

E877

NA49

lt+0gtltgt

Elab

A [GeV]

bull Clear evidence for ldquohornrdquo structure in K+pi+ and

Lambdapi+ at ~30 A GeV

bull Non-horn structure in K-pi-

bull ldquohornrdquo is not reproduced by hadronic transport

models

bull New degrees of freedom

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse T slopes of K+ and K- spectra

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

Au+Au Pb+Pb -gt K++X

T [G

eV]

HSD HSD with Cronin eff UrQMD 20

10 100010

015

020

025

030

035 p+p -gt K++X

T [G

eV]

exp data K+ K0

S

FRITIOF-702 in HSD UrQMD 20

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

HSD HSD with Cronin eff UrQMD 20

Au+Au Pb+Pb -gt K+X

s12 [GeV]

10 100010

015

020

025

030

035 p+p -gt K+X

exp data K K0

S

FRITIOF-702 in HSD UrQMD 20

s12 [GeV]

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse slope is not reproduced by hadronic transport models

New degrees of freedom

Is lsquohornrsquo-effect a signal of PT

J Rafelski Phys Rep 88 (1982) 331

Strangeness as a good signal of deconfinement

Strangeness production In a hadronic matter

N+N -gt N+Λ+K requires ΔE = 670 MeV

π+N -gt Λ+K requires ΔE = 535 MeV

In QGP

- quarks requires ΔE = 300 MeV - cheaper

ss

Models

bull SMES with PT M Gazditzki M Gorenstein 1999

bull Thermal-Statistical HRG Model ndash P Brawn-Munzinger et al (one-component hadronic core with

artificial heavy resonances) ndash K Bugaev et al (multi-component hadronic cores)ndash Others

bull Hadronic Kinetic Model E Kolomeitsev B Tomasic

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Contentbull Motivationbull Strangeness Enhancement From subthreshold yield

of K+-s to lsquoHornrsquo-effect

bull New interpretation of Strangeness Enhancement bull Hyperon Polarization in HICbull Global Polarization of Hyperons

ndash Effects of Strong magnetic field in HICndash Effects of Angular Momentum and Vorticity in HIC

bull Conclusion

Which one of the following scenario is realized

Does a Phase Transition take place in central Heavy Ion Collisions (HIC)

Mixed Phase Critical Endpoint

B

Hadronic

matter

Critical

endpoint

Plasma

Nuclei

Chiral symmetry

broken

Chiral symmetry

restored

Colour

superconductor

Neutron stars

T

1st

order

line

Quark-

Gluon

Space-time Evolution of HIC

~ 10 fmc

Phase diagram ndash artistrsquos view

Phases of strongly interacting nuclear matter

L-G

Phase diagram with triple critical point

Space-time Evolution of HIC

expa

nsio

n

Space-time Evolution of HIC

eg

space

time

Hard Scattering

AuAu

Expan

sion

Hadron-Resonance

Gas

Freeze-out

jet JYg p ppK p L

p

What are we searching for

bull Signatures of phase transition andor mixed phase

bull QCD critical (triple)endpoint

bull Onset of chiral symmetry restoration at high ρB

bull The equation-of-state at high ρB

Observables

Signatures of phase transition andor mixed phase

bull excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

bull transverse mass spectra of kaon

bull particle correlations

QCD critical endpoint

bull excitation function of event-by-event fluctuations (multiplicities Kπ transverse momenta hellip)

Onset of chiral symmetry restoration at high ρB

bull dilepton yield (ρ ω φ rarr e+e-(μ+μ-))

The equation-of-state at high ρB

bull collective flow of hadrons

bull strange particle production at a threshold

bull PT in HIC is not stable state but transient onebull PT evolves in finite spacetime

There is not a crucial signal of PT

Every signal is essentially washed out due to subsequent interactions

Signatures of phase transition

andor mixed phase

Excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

Energy range radics = 2 ndash 11 GeV most interesting

bull Enhanced yield of K+

experiments KaoS at SIS AGS NA49

bull Horn Effect (irregular behaviour of K+

π+

)

bull Kink in Inverse Slope of Kaon pt Distributions

experiments NA49 STAR (BES RHIC program)

Enhanced yield of K+ in subthreshold kaon production

Transport models with NN-interactions

bull underestimate yield of K+

by a factor of 6

bull overestimate yield of K-

J Phys G Nucl Part Phys 27 (2001) 275

KaoS at SIS

RQMD

bull K+

N repulsive potential

bull K-

N attractive potential

bull Momentum dependent Skyrme forces

bull Compression parameter

soft ndash 200 MeV

hard ndash 380 MeV

Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios

100 101 102 103 104000

005

010

015

020

025 y=0

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K++

HSD UrQMD 13

100 101 102 103 104000

005

010

015

020

025 ltK+gtlt+

gt 4

E866 NA49

BRAHMS 5

HSD UrQMD 13

Elab

A [GeV]

100 101 102 103 104

000

005

010

015

020

025

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K

100 101 102 103 104

000

005

010

015

020

025

E866

NA49

BRAHMS 5

ltKgtltgt

100 101 102 103 104000

002

004

006

008

E877

NA49 STAR

(+0)

100 101 102 103 104000

002

004

006

008

E877

NA49

lt+0gtltgt

Elab

A [GeV]

bull Clear evidence for ldquohornrdquo structure in K+pi+ and

Lambdapi+ at ~30 A GeV

bull Non-horn structure in K-pi-

bull ldquohornrdquo is not reproduced by hadronic transport

models

bull New degrees of freedom

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse T slopes of K+ and K- spectra

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

Au+Au Pb+Pb -gt K++X

T [G

eV]

HSD HSD with Cronin eff UrQMD 20

10 100010

015

020

025

030

035 p+p -gt K++X

T [G

eV]

exp data K+ K0

S

FRITIOF-702 in HSD UrQMD 20

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

HSD HSD with Cronin eff UrQMD 20

Au+Au Pb+Pb -gt K+X

s12 [GeV]

10 100010

015

020

025

030

035 p+p -gt K+X

exp data K K0

S

FRITIOF-702 in HSD UrQMD 20

s12 [GeV]

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse slope is not reproduced by hadronic transport models

New degrees of freedom

Is lsquohornrsquo-effect a signal of PT

J Rafelski Phys Rep 88 (1982) 331

Strangeness as a good signal of deconfinement

Strangeness production In a hadronic matter

N+N -gt N+Λ+K requires ΔE = 670 MeV

π+N -gt Λ+K requires ΔE = 535 MeV

In QGP

- quarks requires ΔE = 300 MeV - cheaper

ss

Models

bull SMES with PT M Gazditzki M Gorenstein 1999

bull Thermal-Statistical HRG Model ndash P Brawn-Munzinger et al (one-component hadronic core with

artificial heavy resonances) ndash K Bugaev et al (multi-component hadronic cores)ndash Others

bull Hadronic Kinetic Model E Kolomeitsev B Tomasic

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Which one of the following scenario is realized

Does a Phase Transition take place in central Heavy Ion Collisions (HIC)

Mixed Phase Critical Endpoint

B

Hadronic

matter

Critical

endpoint

Plasma

Nuclei

Chiral symmetry

broken

Chiral symmetry

restored

Colour

superconductor

Neutron stars

T

1st

order

line

Quark-

Gluon

Space-time Evolution of HIC

~ 10 fmc

Phase diagram ndash artistrsquos view

Phases of strongly interacting nuclear matter

L-G

Phase diagram with triple critical point

Space-time Evolution of HIC

expa

nsio

n

Space-time Evolution of HIC

eg

space

time

Hard Scattering

AuAu

Expan

sion

Hadron-Resonance

Gas

Freeze-out

jet JYg p ppK p L

p

What are we searching for

bull Signatures of phase transition andor mixed phase

bull QCD critical (triple)endpoint

bull Onset of chiral symmetry restoration at high ρB

bull The equation-of-state at high ρB

Observables

Signatures of phase transition andor mixed phase

bull excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

bull transverse mass spectra of kaon

bull particle correlations

QCD critical endpoint

bull excitation function of event-by-event fluctuations (multiplicities Kπ transverse momenta hellip)

Onset of chiral symmetry restoration at high ρB

bull dilepton yield (ρ ω φ rarr e+e-(μ+μ-))

The equation-of-state at high ρB

bull collective flow of hadrons

bull strange particle production at a threshold

bull PT in HIC is not stable state but transient onebull PT evolves in finite spacetime

There is not a crucial signal of PT

Every signal is essentially washed out due to subsequent interactions

Signatures of phase transition

andor mixed phase

Excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

Energy range radics = 2 ndash 11 GeV most interesting

bull Enhanced yield of K+

experiments KaoS at SIS AGS NA49

bull Horn Effect (irregular behaviour of K+

π+

)

bull Kink in Inverse Slope of Kaon pt Distributions

experiments NA49 STAR (BES RHIC program)

Enhanced yield of K+ in subthreshold kaon production

Transport models with NN-interactions

bull underestimate yield of K+

by a factor of 6

bull overestimate yield of K-

J Phys G Nucl Part Phys 27 (2001) 275

KaoS at SIS

RQMD

bull K+

N repulsive potential

bull K-

N attractive potential

bull Momentum dependent Skyrme forces

bull Compression parameter

soft ndash 200 MeV

hard ndash 380 MeV

Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios

100 101 102 103 104000

005

010

015

020

025 y=0

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K++

HSD UrQMD 13

100 101 102 103 104000

005

010

015

020

025 ltK+gtlt+

gt 4

E866 NA49

BRAHMS 5

HSD UrQMD 13

Elab

A [GeV]

100 101 102 103 104

000

005

010

015

020

025

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K

100 101 102 103 104

000

005

010

015

020

025

E866

NA49

BRAHMS 5

ltKgtltgt

100 101 102 103 104000

002

004

006

008

E877

NA49 STAR

(+0)

100 101 102 103 104000

002

004

006

008

E877

NA49

lt+0gtltgt

Elab

A [GeV]

bull Clear evidence for ldquohornrdquo structure in K+pi+ and

Lambdapi+ at ~30 A GeV

bull Non-horn structure in K-pi-

bull ldquohornrdquo is not reproduced by hadronic transport

models

bull New degrees of freedom

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse T slopes of K+ and K- spectra

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

Au+Au Pb+Pb -gt K++X

T [G

eV]

HSD HSD with Cronin eff UrQMD 20

10 100010

015

020

025

030

035 p+p -gt K++X

T [G

eV]

exp data K+ K0

S

FRITIOF-702 in HSD UrQMD 20

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

HSD HSD with Cronin eff UrQMD 20

Au+Au Pb+Pb -gt K+X

s12 [GeV]

10 100010

015

020

025

030

035 p+p -gt K+X

exp data K K0

S

FRITIOF-702 in HSD UrQMD 20

s12 [GeV]

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse slope is not reproduced by hadronic transport models

New degrees of freedom

Is lsquohornrsquo-effect a signal of PT

J Rafelski Phys Rep 88 (1982) 331

Strangeness as a good signal of deconfinement

Strangeness production In a hadronic matter

N+N -gt N+Λ+K requires ΔE = 670 MeV

π+N -gt Λ+K requires ΔE = 535 MeV

In QGP

- quarks requires ΔE = 300 MeV - cheaper

ss

Models

bull SMES with PT M Gazditzki M Gorenstein 1999

bull Thermal-Statistical HRG Model ndash P Brawn-Munzinger et al (one-component hadronic core with

artificial heavy resonances) ndash K Bugaev et al (multi-component hadronic cores)ndash Others

bull Hadronic Kinetic Model E Kolomeitsev B Tomasic

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Mixed Phase Critical Endpoint

B

Hadronic

matter

Critical

endpoint

Plasma

Nuclei

Chiral symmetry

broken

Chiral symmetry

restored

Colour

superconductor

Neutron stars

T

1st

order

line

Quark-

Gluon

Space-time Evolution of HIC

~ 10 fmc

Phase diagram ndash artistrsquos view

Phases of strongly interacting nuclear matter

L-G

Phase diagram with triple critical point

Space-time Evolution of HIC

expa

nsio

n

Space-time Evolution of HIC

eg

space

time

Hard Scattering

AuAu

Expan

sion

Hadron-Resonance

Gas

Freeze-out

jet JYg p ppK p L

p

What are we searching for

bull Signatures of phase transition andor mixed phase

bull QCD critical (triple)endpoint

bull Onset of chiral symmetry restoration at high ρB

bull The equation-of-state at high ρB

Observables

Signatures of phase transition andor mixed phase

bull excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

bull transverse mass spectra of kaon

bull particle correlations

QCD critical endpoint

bull excitation function of event-by-event fluctuations (multiplicities Kπ transverse momenta hellip)

Onset of chiral symmetry restoration at high ρB

bull dilepton yield (ρ ω φ rarr e+e-(μ+μ-))

The equation-of-state at high ρB

bull collective flow of hadrons

bull strange particle production at a threshold

bull PT in HIC is not stable state but transient onebull PT evolves in finite spacetime

There is not a crucial signal of PT

Every signal is essentially washed out due to subsequent interactions

Signatures of phase transition

andor mixed phase

Excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

Energy range radics = 2 ndash 11 GeV most interesting

bull Enhanced yield of K+

experiments KaoS at SIS AGS NA49

bull Horn Effect (irregular behaviour of K+

π+

)

bull Kink in Inverse Slope of Kaon pt Distributions

experiments NA49 STAR (BES RHIC program)

Enhanced yield of K+ in subthreshold kaon production

Transport models with NN-interactions

bull underestimate yield of K+

by a factor of 6

bull overestimate yield of K-

J Phys G Nucl Part Phys 27 (2001) 275

KaoS at SIS

RQMD

bull K+

N repulsive potential

bull K-

N attractive potential

bull Momentum dependent Skyrme forces

bull Compression parameter

soft ndash 200 MeV

hard ndash 380 MeV

Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios

100 101 102 103 104000

005

010

015

020

025 y=0

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K++

HSD UrQMD 13

100 101 102 103 104000

005

010

015

020

025 ltK+gtlt+

gt 4

E866 NA49

BRAHMS 5

HSD UrQMD 13

Elab

A [GeV]

100 101 102 103 104

000

005

010

015

020

025

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K

100 101 102 103 104

000

005

010

015

020

025

E866

NA49

BRAHMS 5

ltKgtltgt

100 101 102 103 104000

002

004

006

008

E877

NA49 STAR

(+0)

100 101 102 103 104000

002

004

006

008

E877

NA49

lt+0gtltgt

Elab

A [GeV]

bull Clear evidence for ldquohornrdquo structure in K+pi+ and

Lambdapi+ at ~30 A GeV

bull Non-horn structure in K-pi-

bull ldquohornrdquo is not reproduced by hadronic transport

models

bull New degrees of freedom

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse T slopes of K+ and K- spectra

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

Au+Au Pb+Pb -gt K++X

T [G

eV]

HSD HSD with Cronin eff UrQMD 20

10 100010

015

020

025

030

035 p+p -gt K++X

T [G

eV]

exp data K+ K0

S

FRITIOF-702 in HSD UrQMD 20

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

HSD HSD with Cronin eff UrQMD 20

Au+Au Pb+Pb -gt K+X

s12 [GeV]

10 100010

015

020

025

030

035 p+p -gt K+X

exp data K K0

S

FRITIOF-702 in HSD UrQMD 20

s12 [GeV]

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse slope is not reproduced by hadronic transport models

New degrees of freedom

Is lsquohornrsquo-effect a signal of PT

J Rafelski Phys Rep 88 (1982) 331

Strangeness as a good signal of deconfinement

Strangeness production In a hadronic matter

N+N -gt N+Λ+K requires ΔE = 670 MeV

π+N -gt Λ+K requires ΔE = 535 MeV

In QGP

- quarks requires ΔE = 300 MeV - cheaper

ss

Models

bull SMES with PT M Gazditzki M Gorenstein 1999

bull Thermal-Statistical HRG Model ndash P Brawn-Munzinger et al (one-component hadronic core with

artificial heavy resonances) ndash K Bugaev et al (multi-component hadronic cores)ndash Others

bull Hadronic Kinetic Model E Kolomeitsev B Tomasic

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Space-time Evolution of HIC

~ 10 fmc

Phase diagram ndash artistrsquos view

Phases of strongly interacting nuclear matter

L-G

Phase diagram with triple critical point

Space-time Evolution of HIC

expa

nsio

n

Space-time Evolution of HIC

eg

space

time

Hard Scattering

AuAu

Expan

sion

Hadron-Resonance

Gas

Freeze-out

jet JYg p ppK p L

p

What are we searching for

bull Signatures of phase transition andor mixed phase

bull QCD critical (triple)endpoint

bull Onset of chiral symmetry restoration at high ρB

bull The equation-of-state at high ρB

Observables

Signatures of phase transition andor mixed phase

bull excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

bull transverse mass spectra of kaon

bull particle correlations

QCD critical endpoint

bull excitation function of event-by-event fluctuations (multiplicities Kπ transverse momenta hellip)

Onset of chiral symmetry restoration at high ρB

bull dilepton yield (ρ ω φ rarr e+e-(μ+μ-))

The equation-of-state at high ρB

bull collective flow of hadrons

bull strange particle production at a threshold

bull PT in HIC is not stable state but transient onebull PT evolves in finite spacetime

There is not a crucial signal of PT

Every signal is essentially washed out due to subsequent interactions

Signatures of phase transition

andor mixed phase

Excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

Energy range radics = 2 ndash 11 GeV most interesting

bull Enhanced yield of K+

experiments KaoS at SIS AGS NA49

bull Horn Effect (irregular behaviour of K+

π+

)

bull Kink in Inverse Slope of Kaon pt Distributions

experiments NA49 STAR (BES RHIC program)

Enhanced yield of K+ in subthreshold kaon production

Transport models with NN-interactions

bull underestimate yield of K+

by a factor of 6

bull overestimate yield of K-

J Phys G Nucl Part Phys 27 (2001) 275

KaoS at SIS

RQMD

bull K+

N repulsive potential

bull K-

N attractive potential

bull Momentum dependent Skyrme forces

bull Compression parameter

soft ndash 200 MeV

hard ndash 380 MeV

Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios

100 101 102 103 104000

005

010

015

020

025 y=0

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K++

HSD UrQMD 13

100 101 102 103 104000

005

010

015

020

025 ltK+gtlt+

gt 4

E866 NA49

BRAHMS 5

HSD UrQMD 13

Elab

A [GeV]

100 101 102 103 104

000

005

010

015

020

025

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K

100 101 102 103 104

000

005

010

015

020

025

E866

NA49

BRAHMS 5

ltKgtltgt

100 101 102 103 104000

002

004

006

008

E877

NA49 STAR

(+0)

100 101 102 103 104000

002

004

006

008

E877

NA49

lt+0gtltgt

Elab

A [GeV]

bull Clear evidence for ldquohornrdquo structure in K+pi+ and

Lambdapi+ at ~30 A GeV

bull Non-horn structure in K-pi-

bull ldquohornrdquo is not reproduced by hadronic transport

models

bull New degrees of freedom

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse T slopes of K+ and K- spectra

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

Au+Au Pb+Pb -gt K++X

T [G

eV]

HSD HSD with Cronin eff UrQMD 20

10 100010

015

020

025

030

035 p+p -gt K++X

T [G

eV]

exp data K+ K0

S

FRITIOF-702 in HSD UrQMD 20

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

HSD HSD with Cronin eff UrQMD 20

Au+Au Pb+Pb -gt K+X

s12 [GeV]

10 100010

015

020

025

030

035 p+p -gt K+X

exp data K K0

S

FRITIOF-702 in HSD UrQMD 20

s12 [GeV]

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse slope is not reproduced by hadronic transport models

New degrees of freedom

Is lsquohornrsquo-effect a signal of PT

J Rafelski Phys Rep 88 (1982) 331

Strangeness as a good signal of deconfinement

Strangeness production In a hadronic matter

N+N -gt N+Λ+K requires ΔE = 670 MeV

π+N -gt Λ+K requires ΔE = 535 MeV

In QGP

- quarks requires ΔE = 300 MeV - cheaper

ss

Models

bull SMES with PT M Gazditzki M Gorenstein 1999

bull Thermal-Statistical HRG Model ndash P Brawn-Munzinger et al (one-component hadronic core with

artificial heavy resonances) ndash K Bugaev et al (multi-component hadronic cores)ndash Others

bull Hadronic Kinetic Model E Kolomeitsev B Tomasic

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Phase diagram ndash artistrsquos view

Phases of strongly interacting nuclear matter

L-G

Phase diagram with triple critical point

Space-time Evolution of HIC

expa

nsio

n

Space-time Evolution of HIC

eg

space

time

Hard Scattering

AuAu

Expan

sion

Hadron-Resonance

Gas

Freeze-out

jet JYg p ppK p L

p

What are we searching for

bull Signatures of phase transition andor mixed phase

bull QCD critical (triple)endpoint

bull Onset of chiral symmetry restoration at high ρB

bull The equation-of-state at high ρB

Observables

Signatures of phase transition andor mixed phase

bull excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

bull transverse mass spectra of kaon

bull particle correlations

QCD critical endpoint

bull excitation function of event-by-event fluctuations (multiplicities Kπ transverse momenta hellip)

Onset of chiral symmetry restoration at high ρB

bull dilepton yield (ρ ω φ rarr e+e-(μ+μ-))

The equation-of-state at high ρB

bull collective flow of hadrons

bull strange particle production at a threshold

bull PT in HIC is not stable state but transient onebull PT evolves in finite spacetime

There is not a crucial signal of PT

Every signal is essentially washed out due to subsequent interactions

Signatures of phase transition

andor mixed phase

Excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

Energy range radics = 2 ndash 11 GeV most interesting

bull Enhanced yield of K+

experiments KaoS at SIS AGS NA49

bull Horn Effect (irregular behaviour of K+

π+

)

bull Kink in Inverse Slope of Kaon pt Distributions

experiments NA49 STAR (BES RHIC program)

Enhanced yield of K+ in subthreshold kaon production

Transport models with NN-interactions

bull underestimate yield of K+

by a factor of 6

bull overestimate yield of K-

J Phys G Nucl Part Phys 27 (2001) 275

KaoS at SIS

RQMD

bull K+

N repulsive potential

bull K-

N attractive potential

bull Momentum dependent Skyrme forces

bull Compression parameter

soft ndash 200 MeV

hard ndash 380 MeV

Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios

100 101 102 103 104000

005

010

015

020

025 y=0

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K++

HSD UrQMD 13

100 101 102 103 104000

005

010

015

020

025 ltK+gtlt+

gt 4

E866 NA49

BRAHMS 5

HSD UrQMD 13

Elab

A [GeV]

100 101 102 103 104

000

005

010

015

020

025

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K

100 101 102 103 104

000

005

010

015

020

025

E866

NA49

BRAHMS 5

ltKgtltgt

100 101 102 103 104000

002

004

006

008

E877

NA49 STAR

(+0)

100 101 102 103 104000

002

004

006

008

E877

NA49

lt+0gtltgt

Elab

A [GeV]

bull Clear evidence for ldquohornrdquo structure in K+pi+ and

Lambdapi+ at ~30 A GeV

bull Non-horn structure in K-pi-

bull ldquohornrdquo is not reproduced by hadronic transport

models

bull New degrees of freedom

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse T slopes of K+ and K- spectra

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

Au+Au Pb+Pb -gt K++X

T [G

eV]

HSD HSD with Cronin eff UrQMD 20

10 100010

015

020

025

030

035 p+p -gt K++X

T [G

eV]

exp data K+ K0

S

FRITIOF-702 in HSD UrQMD 20

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

HSD HSD with Cronin eff UrQMD 20

Au+Au Pb+Pb -gt K+X

s12 [GeV]

10 100010

015

020

025

030

035 p+p -gt K+X

exp data K K0

S

FRITIOF-702 in HSD UrQMD 20

s12 [GeV]

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse slope is not reproduced by hadronic transport models

New degrees of freedom

Is lsquohornrsquo-effect a signal of PT

J Rafelski Phys Rep 88 (1982) 331

Strangeness as a good signal of deconfinement

Strangeness production In a hadronic matter

N+N -gt N+Λ+K requires ΔE = 670 MeV

π+N -gt Λ+K requires ΔE = 535 MeV

In QGP

- quarks requires ΔE = 300 MeV - cheaper

ss

Models

bull SMES with PT M Gazditzki M Gorenstein 1999

bull Thermal-Statistical HRG Model ndash P Brawn-Munzinger et al (one-component hadronic core with

artificial heavy resonances) ndash K Bugaev et al (multi-component hadronic cores)ndash Others

bull Hadronic Kinetic Model E Kolomeitsev B Tomasic

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Phase diagram with triple critical point

Space-time Evolution of HIC

expa

nsio

n

Space-time Evolution of HIC

eg

space

time

Hard Scattering

AuAu

Expan

sion

Hadron-Resonance

Gas

Freeze-out

jet JYg p ppK p L

p

What are we searching for

bull Signatures of phase transition andor mixed phase

bull QCD critical (triple)endpoint

bull Onset of chiral symmetry restoration at high ρB

bull The equation-of-state at high ρB

Observables

Signatures of phase transition andor mixed phase

bull excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

bull transverse mass spectra of kaon

bull particle correlations

QCD critical endpoint

bull excitation function of event-by-event fluctuations (multiplicities Kπ transverse momenta hellip)

Onset of chiral symmetry restoration at high ρB

bull dilepton yield (ρ ω φ rarr e+e-(μ+μ-))

The equation-of-state at high ρB

bull collective flow of hadrons

bull strange particle production at a threshold

bull PT in HIC is not stable state but transient onebull PT evolves in finite spacetime

There is not a crucial signal of PT

Every signal is essentially washed out due to subsequent interactions

Signatures of phase transition

andor mixed phase

Excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

Energy range radics = 2 ndash 11 GeV most interesting

bull Enhanced yield of K+

experiments KaoS at SIS AGS NA49

bull Horn Effect (irregular behaviour of K+

π+

)

bull Kink in Inverse Slope of Kaon pt Distributions

experiments NA49 STAR (BES RHIC program)

Enhanced yield of K+ in subthreshold kaon production

Transport models with NN-interactions

bull underestimate yield of K+

by a factor of 6

bull overestimate yield of K-

J Phys G Nucl Part Phys 27 (2001) 275

KaoS at SIS

RQMD

bull K+

N repulsive potential

bull K-

N attractive potential

bull Momentum dependent Skyrme forces

bull Compression parameter

soft ndash 200 MeV

hard ndash 380 MeV

Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios

100 101 102 103 104000

005

010

015

020

025 y=0

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K++

HSD UrQMD 13

100 101 102 103 104000

005

010

015

020

025 ltK+gtlt+

gt 4

E866 NA49

BRAHMS 5

HSD UrQMD 13

Elab

A [GeV]

100 101 102 103 104

000

005

010

015

020

025

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K

100 101 102 103 104

000

005

010

015

020

025

E866

NA49

BRAHMS 5

ltKgtltgt

100 101 102 103 104000

002

004

006

008

E877

NA49 STAR

(+0)

100 101 102 103 104000

002

004

006

008

E877

NA49

lt+0gtltgt

Elab

A [GeV]

bull Clear evidence for ldquohornrdquo structure in K+pi+ and

Lambdapi+ at ~30 A GeV

bull Non-horn structure in K-pi-

bull ldquohornrdquo is not reproduced by hadronic transport

models

bull New degrees of freedom

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse T slopes of K+ and K- spectra

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

Au+Au Pb+Pb -gt K++X

T [G

eV]

HSD HSD with Cronin eff UrQMD 20

10 100010

015

020

025

030

035 p+p -gt K++X

T [G

eV]

exp data K+ K0

S

FRITIOF-702 in HSD UrQMD 20

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

HSD HSD with Cronin eff UrQMD 20

Au+Au Pb+Pb -gt K+X

s12 [GeV]

10 100010

015

020

025

030

035 p+p -gt K+X

exp data K K0

S

FRITIOF-702 in HSD UrQMD 20

s12 [GeV]

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse slope is not reproduced by hadronic transport models

New degrees of freedom

Is lsquohornrsquo-effect a signal of PT

J Rafelski Phys Rep 88 (1982) 331

Strangeness as a good signal of deconfinement

Strangeness production In a hadronic matter

N+N -gt N+Λ+K requires ΔE = 670 MeV

π+N -gt Λ+K requires ΔE = 535 MeV

In QGP

- quarks requires ΔE = 300 MeV - cheaper

ss

Models

bull SMES with PT M Gazditzki M Gorenstein 1999

bull Thermal-Statistical HRG Model ndash P Brawn-Munzinger et al (one-component hadronic core with

artificial heavy resonances) ndash K Bugaev et al (multi-component hadronic cores)ndash Others

bull Hadronic Kinetic Model E Kolomeitsev B Tomasic

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Space-time Evolution of HIC

expa

nsio

n

Space-time Evolution of HIC

eg

space

time

Hard Scattering

AuAu

Expan

sion

Hadron-Resonance

Gas

Freeze-out

jet JYg p ppK p L

p

What are we searching for

bull Signatures of phase transition andor mixed phase

bull QCD critical (triple)endpoint

bull Onset of chiral symmetry restoration at high ρB

bull The equation-of-state at high ρB

Observables

Signatures of phase transition andor mixed phase

bull excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

bull transverse mass spectra of kaon

bull particle correlations

QCD critical endpoint

bull excitation function of event-by-event fluctuations (multiplicities Kπ transverse momenta hellip)

Onset of chiral symmetry restoration at high ρB

bull dilepton yield (ρ ω φ rarr e+e-(μ+μ-))

The equation-of-state at high ρB

bull collective flow of hadrons

bull strange particle production at a threshold

bull PT in HIC is not stable state but transient onebull PT evolves in finite spacetime

There is not a crucial signal of PT

Every signal is essentially washed out due to subsequent interactions

Signatures of phase transition

andor mixed phase

Excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

Energy range radics = 2 ndash 11 GeV most interesting

bull Enhanced yield of K+

experiments KaoS at SIS AGS NA49

bull Horn Effect (irregular behaviour of K+

π+

)

bull Kink in Inverse Slope of Kaon pt Distributions

experiments NA49 STAR (BES RHIC program)

Enhanced yield of K+ in subthreshold kaon production

Transport models with NN-interactions

bull underestimate yield of K+

by a factor of 6

bull overestimate yield of K-

J Phys G Nucl Part Phys 27 (2001) 275

KaoS at SIS

RQMD

bull K+

N repulsive potential

bull K-

N attractive potential

bull Momentum dependent Skyrme forces

bull Compression parameter

soft ndash 200 MeV

hard ndash 380 MeV

Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios

100 101 102 103 104000

005

010

015

020

025 y=0

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K++

HSD UrQMD 13

100 101 102 103 104000

005

010

015

020

025 ltK+gtlt+

gt 4

E866 NA49

BRAHMS 5

HSD UrQMD 13

Elab

A [GeV]

100 101 102 103 104

000

005

010

015

020

025

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K

100 101 102 103 104

000

005

010

015

020

025

E866

NA49

BRAHMS 5

ltKgtltgt

100 101 102 103 104000

002

004

006

008

E877

NA49 STAR

(+0)

100 101 102 103 104000

002

004

006

008

E877

NA49

lt+0gtltgt

Elab

A [GeV]

bull Clear evidence for ldquohornrdquo structure in K+pi+ and

Lambdapi+ at ~30 A GeV

bull Non-horn structure in K-pi-

bull ldquohornrdquo is not reproduced by hadronic transport

models

bull New degrees of freedom

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse T slopes of K+ and K- spectra

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

Au+Au Pb+Pb -gt K++X

T [G

eV]

HSD HSD with Cronin eff UrQMD 20

10 100010

015

020

025

030

035 p+p -gt K++X

T [G

eV]

exp data K+ K0

S

FRITIOF-702 in HSD UrQMD 20

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

HSD HSD with Cronin eff UrQMD 20

Au+Au Pb+Pb -gt K+X

s12 [GeV]

10 100010

015

020

025

030

035 p+p -gt K+X

exp data K K0

S

FRITIOF-702 in HSD UrQMD 20

s12 [GeV]

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse slope is not reproduced by hadronic transport models

New degrees of freedom

Is lsquohornrsquo-effect a signal of PT

J Rafelski Phys Rep 88 (1982) 331

Strangeness as a good signal of deconfinement

Strangeness production In a hadronic matter

N+N -gt N+Λ+K requires ΔE = 670 MeV

π+N -gt Λ+K requires ΔE = 535 MeV

In QGP

- quarks requires ΔE = 300 MeV - cheaper

ss

Models

bull SMES with PT M Gazditzki M Gorenstein 1999

bull Thermal-Statistical HRG Model ndash P Brawn-Munzinger et al (one-component hadronic core with

artificial heavy resonances) ndash K Bugaev et al (multi-component hadronic cores)ndash Others

bull Hadronic Kinetic Model E Kolomeitsev B Tomasic

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Space-time Evolution of HIC

eg

space

time

Hard Scattering

AuAu

Expan

sion

Hadron-Resonance

Gas

Freeze-out

jet JYg p ppK p L

p

What are we searching for

bull Signatures of phase transition andor mixed phase

bull QCD critical (triple)endpoint

bull Onset of chiral symmetry restoration at high ρB

bull The equation-of-state at high ρB

Observables

Signatures of phase transition andor mixed phase

bull excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

bull transverse mass spectra of kaon

bull particle correlations

QCD critical endpoint

bull excitation function of event-by-event fluctuations (multiplicities Kπ transverse momenta hellip)

Onset of chiral symmetry restoration at high ρB

bull dilepton yield (ρ ω φ rarr e+e-(μ+μ-))

The equation-of-state at high ρB

bull collective flow of hadrons

bull strange particle production at a threshold

bull PT in HIC is not stable state but transient onebull PT evolves in finite spacetime

There is not a crucial signal of PT

Every signal is essentially washed out due to subsequent interactions

Signatures of phase transition

andor mixed phase

Excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

Energy range radics = 2 ndash 11 GeV most interesting

bull Enhanced yield of K+

experiments KaoS at SIS AGS NA49

bull Horn Effect (irregular behaviour of K+

π+

)

bull Kink in Inverse Slope of Kaon pt Distributions

experiments NA49 STAR (BES RHIC program)

Enhanced yield of K+ in subthreshold kaon production

Transport models with NN-interactions

bull underestimate yield of K+

by a factor of 6

bull overestimate yield of K-

J Phys G Nucl Part Phys 27 (2001) 275

KaoS at SIS

RQMD

bull K+

N repulsive potential

bull K-

N attractive potential

bull Momentum dependent Skyrme forces

bull Compression parameter

soft ndash 200 MeV

hard ndash 380 MeV

Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios

100 101 102 103 104000

005

010

015

020

025 y=0

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K++

HSD UrQMD 13

100 101 102 103 104000

005

010

015

020

025 ltK+gtlt+

gt 4

E866 NA49

BRAHMS 5

HSD UrQMD 13

Elab

A [GeV]

100 101 102 103 104

000

005

010

015

020

025

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K

100 101 102 103 104

000

005

010

015

020

025

E866

NA49

BRAHMS 5

ltKgtltgt

100 101 102 103 104000

002

004

006

008

E877

NA49 STAR

(+0)

100 101 102 103 104000

002

004

006

008

E877

NA49

lt+0gtltgt

Elab

A [GeV]

bull Clear evidence for ldquohornrdquo structure in K+pi+ and

Lambdapi+ at ~30 A GeV

bull Non-horn structure in K-pi-

bull ldquohornrdquo is not reproduced by hadronic transport

models

bull New degrees of freedom

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse T slopes of K+ and K- spectra

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

Au+Au Pb+Pb -gt K++X

T [G

eV]

HSD HSD with Cronin eff UrQMD 20

10 100010

015

020

025

030

035 p+p -gt K++X

T [G

eV]

exp data K+ K0

S

FRITIOF-702 in HSD UrQMD 20

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

HSD HSD with Cronin eff UrQMD 20

Au+Au Pb+Pb -gt K+X

s12 [GeV]

10 100010

015

020

025

030

035 p+p -gt K+X

exp data K K0

S

FRITIOF-702 in HSD UrQMD 20

s12 [GeV]

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse slope is not reproduced by hadronic transport models

New degrees of freedom

Is lsquohornrsquo-effect a signal of PT

J Rafelski Phys Rep 88 (1982) 331

Strangeness as a good signal of deconfinement

Strangeness production In a hadronic matter

N+N -gt N+Λ+K requires ΔE = 670 MeV

π+N -gt Λ+K requires ΔE = 535 MeV

In QGP

- quarks requires ΔE = 300 MeV - cheaper

ss

Models

bull SMES with PT M Gazditzki M Gorenstein 1999

bull Thermal-Statistical HRG Model ndash P Brawn-Munzinger et al (one-component hadronic core with

artificial heavy resonances) ndash K Bugaev et al (multi-component hadronic cores)ndash Others

bull Hadronic Kinetic Model E Kolomeitsev B Tomasic

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

What are we searching for

bull Signatures of phase transition andor mixed phase

bull QCD critical (triple)endpoint

bull Onset of chiral symmetry restoration at high ρB

bull The equation-of-state at high ρB

Observables

Signatures of phase transition andor mixed phase

bull excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

bull transverse mass spectra of kaon

bull particle correlations

QCD critical endpoint

bull excitation function of event-by-event fluctuations (multiplicities Kπ transverse momenta hellip)

Onset of chiral symmetry restoration at high ρB

bull dilepton yield (ρ ω φ rarr e+e-(μ+μ-))

The equation-of-state at high ρB

bull collective flow of hadrons

bull strange particle production at a threshold

bull PT in HIC is not stable state but transient onebull PT evolves in finite spacetime

There is not a crucial signal of PT

Every signal is essentially washed out due to subsequent interactions

Signatures of phase transition

andor mixed phase

Excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

Energy range radics = 2 ndash 11 GeV most interesting

bull Enhanced yield of K+

experiments KaoS at SIS AGS NA49

bull Horn Effect (irregular behaviour of K+

π+

)

bull Kink in Inverse Slope of Kaon pt Distributions

experiments NA49 STAR (BES RHIC program)

Enhanced yield of K+ in subthreshold kaon production

Transport models with NN-interactions

bull underestimate yield of K+

by a factor of 6

bull overestimate yield of K-

J Phys G Nucl Part Phys 27 (2001) 275

KaoS at SIS

RQMD

bull K+

N repulsive potential

bull K-

N attractive potential

bull Momentum dependent Skyrme forces

bull Compression parameter

soft ndash 200 MeV

hard ndash 380 MeV

Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios

100 101 102 103 104000

005

010

015

020

025 y=0

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K++

HSD UrQMD 13

100 101 102 103 104000

005

010

015

020

025 ltK+gtlt+

gt 4

E866 NA49

BRAHMS 5

HSD UrQMD 13

Elab

A [GeV]

100 101 102 103 104

000

005

010

015

020

025

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K

100 101 102 103 104

000

005

010

015

020

025

E866

NA49

BRAHMS 5

ltKgtltgt

100 101 102 103 104000

002

004

006

008

E877

NA49 STAR

(+0)

100 101 102 103 104000

002

004

006

008

E877

NA49

lt+0gtltgt

Elab

A [GeV]

bull Clear evidence for ldquohornrdquo structure in K+pi+ and

Lambdapi+ at ~30 A GeV

bull Non-horn structure in K-pi-

bull ldquohornrdquo is not reproduced by hadronic transport

models

bull New degrees of freedom

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse T slopes of K+ and K- spectra

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

Au+Au Pb+Pb -gt K++X

T [G

eV]

HSD HSD with Cronin eff UrQMD 20

10 100010

015

020

025

030

035 p+p -gt K++X

T [G

eV]

exp data K+ K0

S

FRITIOF-702 in HSD UrQMD 20

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

HSD HSD with Cronin eff UrQMD 20

Au+Au Pb+Pb -gt K+X

s12 [GeV]

10 100010

015

020

025

030

035 p+p -gt K+X

exp data K K0

S

FRITIOF-702 in HSD UrQMD 20

s12 [GeV]

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse slope is not reproduced by hadronic transport models

New degrees of freedom

Is lsquohornrsquo-effect a signal of PT

J Rafelski Phys Rep 88 (1982) 331

Strangeness as a good signal of deconfinement

Strangeness production In a hadronic matter

N+N -gt N+Λ+K requires ΔE = 670 MeV

π+N -gt Λ+K requires ΔE = 535 MeV

In QGP

- quarks requires ΔE = 300 MeV - cheaper

ss

Models

bull SMES with PT M Gazditzki M Gorenstein 1999

bull Thermal-Statistical HRG Model ndash P Brawn-Munzinger et al (one-component hadronic core with

artificial heavy resonances) ndash K Bugaev et al (multi-component hadronic cores)ndash Others

bull Hadronic Kinetic Model E Kolomeitsev B Tomasic

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Observables

Signatures of phase transition andor mixed phase

bull excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

bull transverse mass spectra of kaon

bull particle correlations

QCD critical endpoint

bull excitation function of event-by-event fluctuations (multiplicities Kπ transverse momenta hellip)

Onset of chiral symmetry restoration at high ρB

bull dilepton yield (ρ ω φ rarr e+e-(μ+μ-))

The equation-of-state at high ρB

bull collective flow of hadrons

bull strange particle production at a threshold

bull PT in HIC is not stable state but transient onebull PT evolves in finite spacetime

There is not a crucial signal of PT

Every signal is essentially washed out due to subsequent interactions

Signatures of phase transition

andor mixed phase

Excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

Energy range radics = 2 ndash 11 GeV most interesting

bull Enhanced yield of K+

experiments KaoS at SIS AGS NA49

bull Horn Effect (irregular behaviour of K+

π+

)

bull Kink in Inverse Slope of Kaon pt Distributions

experiments NA49 STAR (BES RHIC program)

Enhanced yield of K+ in subthreshold kaon production

Transport models with NN-interactions

bull underestimate yield of K+

by a factor of 6

bull overestimate yield of K-

J Phys G Nucl Part Phys 27 (2001) 275

KaoS at SIS

RQMD

bull K+

N repulsive potential

bull K-

N attractive potential

bull Momentum dependent Skyrme forces

bull Compression parameter

soft ndash 200 MeV

hard ndash 380 MeV

Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios

100 101 102 103 104000

005

010

015

020

025 y=0

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K++

HSD UrQMD 13

100 101 102 103 104000

005

010

015

020

025 ltK+gtlt+

gt 4

E866 NA49

BRAHMS 5

HSD UrQMD 13

Elab

A [GeV]

100 101 102 103 104

000

005

010

015

020

025

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K

100 101 102 103 104

000

005

010

015

020

025

E866

NA49

BRAHMS 5

ltKgtltgt

100 101 102 103 104000

002

004

006

008

E877

NA49 STAR

(+0)

100 101 102 103 104000

002

004

006

008

E877

NA49

lt+0gtltgt

Elab

A [GeV]

bull Clear evidence for ldquohornrdquo structure in K+pi+ and

Lambdapi+ at ~30 A GeV

bull Non-horn structure in K-pi-

bull ldquohornrdquo is not reproduced by hadronic transport

models

bull New degrees of freedom

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse T slopes of K+ and K- spectra

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

Au+Au Pb+Pb -gt K++X

T [G

eV]

HSD HSD with Cronin eff UrQMD 20

10 100010

015

020

025

030

035 p+p -gt K++X

T [G

eV]

exp data K+ K0

S

FRITIOF-702 in HSD UrQMD 20

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

HSD HSD with Cronin eff UrQMD 20

Au+Au Pb+Pb -gt K+X

s12 [GeV]

10 100010

015

020

025

030

035 p+p -gt K+X

exp data K K0

S

FRITIOF-702 in HSD UrQMD 20

s12 [GeV]

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse slope is not reproduced by hadronic transport models

New degrees of freedom

Is lsquohornrsquo-effect a signal of PT

J Rafelski Phys Rep 88 (1982) 331

Strangeness as a good signal of deconfinement

Strangeness production In a hadronic matter

N+N -gt N+Λ+K requires ΔE = 670 MeV

π+N -gt Λ+K requires ΔE = 535 MeV

In QGP

- quarks requires ΔE = 300 MeV - cheaper

ss

Models

bull SMES with PT M Gazditzki M Gorenstein 1999

bull Thermal-Statistical HRG Model ndash P Brawn-Munzinger et al (one-component hadronic core with

artificial heavy resonances) ndash K Bugaev et al (multi-component hadronic cores)ndash Others

bull Hadronic Kinetic Model E Kolomeitsev B Tomasic

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

bull PT in HIC is not stable state but transient onebull PT evolves in finite spacetime

There is not a crucial signal of PT

Every signal is essentially washed out due to subsequent interactions

Signatures of phase transition

andor mixed phase

Excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

Energy range radics = 2 ndash 11 GeV most interesting

bull Enhanced yield of K+

experiments KaoS at SIS AGS NA49

bull Horn Effect (irregular behaviour of K+

π+

)

bull Kink in Inverse Slope of Kaon pt Distributions

experiments NA49 STAR (BES RHIC program)

Enhanced yield of K+ in subthreshold kaon production

Transport models with NN-interactions

bull underestimate yield of K+

by a factor of 6

bull overestimate yield of K-

J Phys G Nucl Part Phys 27 (2001) 275

KaoS at SIS

RQMD

bull K+

N repulsive potential

bull K-

N attractive potential

bull Momentum dependent Skyrme forces

bull Compression parameter

soft ndash 200 MeV

hard ndash 380 MeV

Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios

100 101 102 103 104000

005

010

015

020

025 y=0

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K++

HSD UrQMD 13

100 101 102 103 104000

005

010

015

020

025 ltK+gtlt+

gt 4

E866 NA49

BRAHMS 5

HSD UrQMD 13

Elab

A [GeV]

100 101 102 103 104

000

005

010

015

020

025

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K

100 101 102 103 104

000

005

010

015

020

025

E866

NA49

BRAHMS 5

ltKgtltgt

100 101 102 103 104000

002

004

006

008

E877

NA49 STAR

(+0)

100 101 102 103 104000

002

004

006

008

E877

NA49

lt+0gtltgt

Elab

A [GeV]

bull Clear evidence for ldquohornrdquo structure in K+pi+ and

Lambdapi+ at ~30 A GeV

bull Non-horn structure in K-pi-

bull ldquohornrdquo is not reproduced by hadronic transport

models

bull New degrees of freedom

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse T slopes of K+ and K- spectra

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

Au+Au Pb+Pb -gt K++X

T [G

eV]

HSD HSD with Cronin eff UrQMD 20

10 100010

015

020

025

030

035 p+p -gt K++X

T [G

eV]

exp data K+ K0

S

FRITIOF-702 in HSD UrQMD 20

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

HSD HSD with Cronin eff UrQMD 20

Au+Au Pb+Pb -gt K+X

s12 [GeV]

10 100010

015

020

025

030

035 p+p -gt K+X

exp data K K0

S

FRITIOF-702 in HSD UrQMD 20

s12 [GeV]

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse slope is not reproduced by hadronic transport models

New degrees of freedom

Is lsquohornrsquo-effect a signal of PT

J Rafelski Phys Rep 88 (1982) 331

Strangeness as a good signal of deconfinement

Strangeness production In a hadronic matter

N+N -gt N+Λ+K requires ΔE = 670 MeV

π+N -gt Λ+K requires ΔE = 535 MeV

In QGP

- quarks requires ΔE = 300 MeV - cheaper

ss

Models

bull SMES with PT M Gazditzki M Gorenstein 1999

bull Thermal-Statistical HRG Model ndash P Brawn-Munzinger et al (one-component hadronic core with

artificial heavy resonances) ndash K Bugaev et al (multi-component hadronic cores)ndash Others

bull Hadronic Kinetic Model E Kolomeitsev B Tomasic

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Excitation function of particle yields and ratios (π K Λ Σ Ξ Ω)

Energy range radics = 2 ndash 11 GeV most interesting

bull Enhanced yield of K+

experiments KaoS at SIS AGS NA49

bull Horn Effect (irregular behaviour of K+

π+

)

bull Kink in Inverse Slope of Kaon pt Distributions

experiments NA49 STAR (BES RHIC program)

Enhanced yield of K+ in subthreshold kaon production

Transport models with NN-interactions

bull underestimate yield of K+

by a factor of 6

bull overestimate yield of K-

J Phys G Nucl Part Phys 27 (2001) 275

KaoS at SIS

RQMD

bull K+

N repulsive potential

bull K-

N attractive potential

bull Momentum dependent Skyrme forces

bull Compression parameter

soft ndash 200 MeV

hard ndash 380 MeV

Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios

100 101 102 103 104000

005

010

015

020

025 y=0

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K++

HSD UrQMD 13

100 101 102 103 104000

005

010

015

020

025 ltK+gtlt+

gt 4

E866 NA49

BRAHMS 5

HSD UrQMD 13

Elab

A [GeV]

100 101 102 103 104

000

005

010

015

020

025

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K

100 101 102 103 104

000

005

010

015

020

025

E866

NA49

BRAHMS 5

ltKgtltgt

100 101 102 103 104000

002

004

006

008

E877

NA49 STAR

(+0)

100 101 102 103 104000

002

004

006

008

E877

NA49

lt+0gtltgt

Elab

A [GeV]

bull Clear evidence for ldquohornrdquo structure in K+pi+ and

Lambdapi+ at ~30 A GeV

bull Non-horn structure in K-pi-

bull ldquohornrdquo is not reproduced by hadronic transport

models

bull New degrees of freedom

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse T slopes of K+ and K- spectra

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

Au+Au Pb+Pb -gt K++X

T [G

eV]

HSD HSD with Cronin eff UrQMD 20

10 100010

015

020

025

030

035 p+p -gt K++X

T [G

eV]

exp data K+ K0

S

FRITIOF-702 in HSD UrQMD 20

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

HSD HSD with Cronin eff UrQMD 20

Au+Au Pb+Pb -gt K+X

s12 [GeV]

10 100010

015

020

025

030

035 p+p -gt K+X

exp data K K0

S

FRITIOF-702 in HSD UrQMD 20

s12 [GeV]

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse slope is not reproduced by hadronic transport models

New degrees of freedom

Is lsquohornrsquo-effect a signal of PT

J Rafelski Phys Rep 88 (1982) 331

Strangeness as a good signal of deconfinement

Strangeness production In a hadronic matter

N+N -gt N+Λ+K requires ΔE = 670 MeV

π+N -gt Λ+K requires ΔE = 535 MeV

In QGP

- quarks requires ΔE = 300 MeV - cheaper

ss

Models

bull SMES with PT M Gazditzki M Gorenstein 1999

bull Thermal-Statistical HRG Model ndash P Brawn-Munzinger et al (one-component hadronic core with

artificial heavy resonances) ndash K Bugaev et al (multi-component hadronic cores)ndash Others

bull Hadronic Kinetic Model E Kolomeitsev B Tomasic

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Enhanced yield of K+ in subthreshold kaon production

Transport models with NN-interactions

bull underestimate yield of K+

by a factor of 6

bull overestimate yield of K-

J Phys G Nucl Part Phys 27 (2001) 275

KaoS at SIS

RQMD

bull K+

N repulsive potential

bull K-

N attractive potential

bull Momentum dependent Skyrme forces

bull Compression parameter

soft ndash 200 MeV

hard ndash 380 MeV

Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios

100 101 102 103 104000

005

010

015

020

025 y=0

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K++

HSD UrQMD 13

100 101 102 103 104000

005

010

015

020

025 ltK+gtlt+

gt 4

E866 NA49

BRAHMS 5

HSD UrQMD 13

Elab

A [GeV]

100 101 102 103 104

000

005

010

015

020

025

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K

100 101 102 103 104

000

005

010

015

020

025

E866

NA49

BRAHMS 5

ltKgtltgt

100 101 102 103 104000

002

004

006

008

E877

NA49 STAR

(+0)

100 101 102 103 104000

002

004

006

008

E877

NA49

lt+0gtltgt

Elab

A [GeV]

bull Clear evidence for ldquohornrdquo structure in K+pi+ and

Lambdapi+ at ~30 A GeV

bull Non-horn structure in K-pi-

bull ldquohornrdquo is not reproduced by hadronic transport

models

bull New degrees of freedom

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse T slopes of K+ and K- spectra

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

Au+Au Pb+Pb -gt K++X

T [G

eV]

HSD HSD with Cronin eff UrQMD 20

10 100010

015

020

025

030

035 p+p -gt K++X

T [G

eV]

exp data K+ K0

S

FRITIOF-702 in HSD UrQMD 20

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

HSD HSD with Cronin eff UrQMD 20

Au+Au Pb+Pb -gt K+X

s12 [GeV]

10 100010

015

020

025

030

035 p+p -gt K+X

exp data K K0

S

FRITIOF-702 in HSD UrQMD 20

s12 [GeV]

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse slope is not reproduced by hadronic transport models

New degrees of freedom

Is lsquohornrsquo-effect a signal of PT

J Rafelski Phys Rep 88 (1982) 331

Strangeness as a good signal of deconfinement

Strangeness production In a hadronic matter

N+N -gt N+Λ+K requires ΔE = 670 MeV

π+N -gt Λ+K requires ΔE = 535 MeV

In QGP

- quarks requires ΔE = 300 MeV - cheaper

ss

Models

bull SMES with PT M Gazditzki M Gorenstein 1999

bull Thermal-Statistical HRG Model ndash P Brawn-Munzinger et al (one-component hadronic core with

artificial heavy resonances) ndash K Bugaev et al (multi-component hadronic cores)ndash Others

bull Hadronic Kinetic Model E Kolomeitsev B Tomasic

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios

100 101 102 103 104000

005

010

015

020

025 y=0

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K++

HSD UrQMD 13

100 101 102 103 104000

005

010

015

020

025 ltK+gtlt+

gt 4

E866 NA49

BRAHMS 5

HSD UrQMD 13

Elab

A [GeV]

100 101 102 103 104

000

005

010

015

020

025

E866 NA49

PHENIX STAR

BRAHMS 5

BRAHMS 10

K

100 101 102 103 104

000

005

010

015

020

025

E866

NA49

BRAHMS 5

ltKgtltgt

100 101 102 103 104000

002

004

006

008

E877

NA49 STAR

(+0)

100 101 102 103 104000

002

004

006

008

E877

NA49

lt+0gtltgt

Elab

A [GeV]

bull Clear evidence for ldquohornrdquo structure in K+pi+ and

Lambdapi+ at ~30 A GeV

bull Non-horn structure in K-pi-

bull ldquohornrdquo is not reproduced by hadronic transport

models

bull New degrees of freedom

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse T slopes of K+ and K- spectra

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

Au+Au Pb+Pb -gt K++X

T [G

eV]

HSD HSD with Cronin eff UrQMD 20

10 100010

015

020

025

030

035 p+p -gt K++X

T [G

eV]

exp data K+ K0

S

FRITIOF-702 in HSD UrQMD 20

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

HSD HSD with Cronin eff UrQMD 20

Au+Au Pb+Pb -gt K+X

s12 [GeV]

10 100010

015

020

025

030

035 p+p -gt K+X

exp data K K0

S

FRITIOF-702 in HSD UrQMD 20

s12 [GeV]

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse slope is not reproduced by hadronic transport models

New degrees of freedom

Is lsquohornrsquo-effect a signal of PT

J Rafelski Phys Rep 88 (1982) 331

Strangeness as a good signal of deconfinement

Strangeness production In a hadronic matter

N+N -gt N+Λ+K requires ΔE = 670 MeV

π+N -gt Λ+K requires ΔE = 535 MeV

In QGP

- quarks requires ΔE = 300 MeV - cheaper

ss

Models

bull SMES with PT M Gazditzki M Gorenstein 1999

bull Thermal-Statistical HRG Model ndash P Brawn-Munzinger et al (one-component hadronic core with

artificial heavy resonances) ndash K Bugaev et al (multi-component hadronic cores)ndash Others

bull Hadronic Kinetic Model E Kolomeitsev B Tomasic

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Inverse T slopes of K+ and K- spectra

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

Au+Au Pb+Pb -gt K++X

T [G

eV]

HSD HSD with Cronin eff UrQMD 20

10 100010

015

020

025

030

035 p+p -gt K++X

T [G

eV]

exp data K+ K0

S

FRITIOF-702 in HSD UrQMD 20

10 100010

015

020

025

030

035

E866 NA49

NA44 STAR

BRAHMS PHENIX

HSD HSD with Cronin eff UrQMD 20

Au+Au Pb+Pb -gt K+X

s12 [GeV]

10 100010

015

020

025

030

035 p+p -gt K+X

exp data K K0

S

FRITIOF-702 in HSD UrQMD 20

s12 [GeV]

PhysRev C69 (2004) 015202 PRL 92 (2004)

013302

Inverse slope is not reproduced by hadronic transport models

New degrees of freedom

Is lsquohornrsquo-effect a signal of PT

J Rafelski Phys Rep 88 (1982) 331

Strangeness as a good signal of deconfinement

Strangeness production In a hadronic matter

N+N -gt N+Λ+K requires ΔE = 670 MeV

π+N -gt Λ+K requires ΔE = 535 MeV

In QGP

- quarks requires ΔE = 300 MeV - cheaper

ss

Models

bull SMES with PT M Gazditzki M Gorenstein 1999

bull Thermal-Statistical HRG Model ndash P Brawn-Munzinger et al (one-component hadronic core with

artificial heavy resonances) ndash K Bugaev et al (multi-component hadronic cores)ndash Others

bull Hadronic Kinetic Model E Kolomeitsev B Tomasic

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Is lsquohornrsquo-effect a signal of PT

J Rafelski Phys Rep 88 (1982) 331

Strangeness as a good signal of deconfinement

Strangeness production In a hadronic matter

N+N -gt N+Λ+K requires ΔE = 670 MeV

π+N -gt Λ+K requires ΔE = 535 MeV

In QGP

- quarks requires ΔE = 300 MeV - cheaper

ss

Models

bull SMES with PT M Gazditzki M Gorenstein 1999

bull Thermal-Statistical HRG Model ndash P Brawn-Munzinger et al (one-component hadronic core with

artificial heavy resonances) ndash K Bugaev et al (multi-component hadronic cores)ndash Others

bull Hadronic Kinetic Model E Kolomeitsev B Tomasic

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Models

bull SMES with PT M Gazditzki M Gorenstein 1999

bull Thermal-Statistical HRG Model ndash P Brawn-Munzinger et al (one-component hadronic core with

artificial heavy resonances) ndash K Bugaev et al (multi-component hadronic cores)ndash Others

bull Hadronic Kinetic Model E Kolomeitsev B Tomasic

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Models

SMES M Gaacutezdzicki MI Gorenstein Acta Phys Polon B 30 (1999) 2705

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Models

SMES M Gazditzki M Gorenstein

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

ModelsHRG P Brawn-Munzinger et albull One-component with artificial heavy resonancesbull parameters are the chemical freeze-out temperature

T the baryo-chemical potential μb and the fireball volume V

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

ModelsK Bugaev et al

HRG model with multi-component hard-core radii Rπ RK RB Rm

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

The strangeness production in a HIC is controlled by

bull fireball expansion

bull available energy (energy density) for strangeness production ~ collision energy

bull temporal evolution of a HIC (fireball lifetime)

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

bull Initial K+ content estimated from pp (pn nn) collisions

bull Rescattering production and annihilation in binary collisions

bull Fireball freezout fix the final state FO BFO

bull Parameters the initial 0 and the lifetime T

Inputs

The time needed for a strangeness production T is about 15-20 fmc

In hydro the typical expansion time is lt10 fmc

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

ModelsNon-equilibrium Kinetic Model E Kolomeitsev B Tomasik

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

FAIRndashNICA Energy Range

ldquoHornrdquo and ldquoKinkrdquo effects are of most interest

Are them a manifestation of phase transition from HP to QGP

Not likely

Then of what

bull How nucleons behave under high compression and do they change their properties

Like ρ ω φ

Conjecture

Nucleons transit to hypronic states

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Central HIC

Baryon density evolution

bull In overlap region nucleons are suppressed

and forced to occupy much less space

volume

bull Overlap time

τO = [2RA(γβ)]bSP

bull For central AuAu-collisions at energies

below lsquohornrsquo

τO ge 1 fm-1

Above lsquohornrsquo

τO 0

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Nucleon Transition into Hyperon Phase

How do nucleons transform into hyperons

bull Inside compressed nuclear matter a strange quark-antiquark condensate is created

Andbull u and d quarks in nucleons are replaced by s quarks and

antiquarks binding with the formers form kaons

p n hyperons + kaonsbull the heavier quark content of a baryon the less spatial

dimensions it occupiesbull Produced kaons are rejected from the compressed zone

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

bull Initial stage of a central fireball formation

Nucleons transformation to hyperons

~ (τO τre)α

f(ρ)

τO - overlap time

τre ~ 1fm-1

- rearrangement time

f(ρ) ndash nucleon hyperon probability

bull Expansion of the central fireball

Non-equilibrium kinetic mechanism

~ 1λint ~ ρσhN

λ - mean free path

σhB - hadron-baryon cross section

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Enchancment Mechanism in HICB

aryo

n D

ensi

tyB

aryo

n D

ensi

ty

Ove

rlap

Tim

e

Kπ

Λπ

Collision EnergyCollision Energy

Kπ and Λπ ratio

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

But why lsquohornrsquo structure takes place for K+π+

but not for K-π- K

+π

+

K- π

-

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Proton Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

00

0

0

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

sduuudp

Only K+

and K0

are produced

No one K- is created

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Neutron Transformations channels

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

)(

0

0

00

00

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

sduuddn

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Higher Collision Energies

KK

KK

SsdKsuKsss

SsuKsdKuss

suKdss

SsuKuds

sdKuusuudp

0

0

0

00

0

0

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Higher Collision Energies

KK

KK

SsuKsdKsss

SsuKsdKdss

sdKuss

SsdKuds

suKddsddun

0

0

0

0

00

00

3 3 )()(2)(

2 2 )()()(

)(2)(

1 1 )()(

)()()(

Only K+

and K0

are produced

No one K- is created

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Hyperon Resonances Decay

8

24

68

100

12 88

12

88

0

0

0

00

00

K

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Stangeness Production in central HIC

AGS Kinetic + Transition mechanismsbull Nucleons transform to Δ- isobars and hyperons + kaons

(τoτre) gt 1

NICA CBM low SPS Kinetic + Transition mechanismsbull Nucleons transform to (multi)strange hyperons + kaons

1 le (τoτre) le 1

RHIC LHC Kinetic mechanism

(τoτre) laquo 1

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

What could be studied in BMampN-NICA-FAIR energy region

bull Enhanced yield of positive and neutral kaons near thresholdbull Enhanced yield of one double and triple strange baryons near

thresholdbull Electromagnetic and weak decays of hyperons below thresholdbull EoS near thresholdbull Correlation of kaons with hyperonsbull Elliptic and direct flows of hyperonsbull Possible Polarization of hyperons

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Neutron star Gravitational compression

NS core

Nuclear matter

Δ- isobar matter

Hyperonic matter

hellip

com

pres

sion

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

On Hyperon Polarization in Heavy Ion Collisions

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Contentbull Introductionbull Global polarization (GP) in HICbull Effects of Strong magnetic field in HICbull Effects of Angular Momentum and Vorticity in HICbull Measurement of Global Polarization of Hyperons

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

IntroductionPolarization of Hyperons in unpolarized pp and pA experiments

FNAL p + Be Λ + X at Ep = 300 GeV GBunce et al PRL 36 1113

Are Hyperons polarized in HIC experiments

E896 (AGS) Au+Au at E = 11 AGeV R Bellwied et al Nucl Phys A698 (2002) 499c

Polarization in Au+Au is the same as in pp and pA

Recombination Models Lund DeGrandampMiettinen

E896

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Introduction

bull Polarization of Λrsquos in unpolarized pp pA and AuAu experiments was detected wrt the production plane

bull Mechanism of polarization in all processes is the same

Hyperons formed in QGP Liang Z and Wang X N 2005 Phys Rev Lett 94 102301

Global Polarization of Hyperons

polarization wrt the reaction plane

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Production Plane Reaction Plane

Definitions

Λ pπ- Au + Au

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Global Hyperon Polarization in AuAuPbPb ndash collisions

ndash NA49 (SPS radics = 172 GeV) - no evidencendash STAR (RHIC radics = 62 200 GeV) - no evidence

Interpretation

Formation of QGP randomizes orientation of u d s ndash quarks spins Therefore the spins of hyperons have no preferred direction

bull However at NA49 and STAR Hyperon polarization was not measured wrt the production

plane Should exist in HIC like in pp and pA collisions (E896

atAGS)

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Global Hyperon Polarization

Conjecture Global polarization in HIC could take place at lower energies (CBM NICA BES RHIC)

HIC at CBM NICA BES RHIC Energiesbull Maximal density of baryonic matterbull Hyperons are created at the initial state (hyperon PT)

Possible reasons of the global polarizationbull Strong magnetic field in semi-central eventsbull Very large angular momentum of a nuclear matter in semi-central

events

)

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Global Polarization induced by Magnetic Field created in HIC

Au + Au A = 197 Z = +79

Strong Magnetic Field

By

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Magnetic Field created in HIC

1010

0750050

5 Au Au

114s energiesNICA At

)(

1 )(

13960907

1216

2

NN

3

2

EM

TeslaGaussB

meB

fmbat

GeV

RvvRR

-vZxtBe

l-tharXivenucet alSkokovV

y

y

ii

iii

i

ii

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Particle polarization in presence of magnetic field

kT

EEnn

kT

E

kT

E

kT

En

kT

E

kT

E

kT

En

BEBE

2

1

2

1

2

1P

states theofocupation in difference the-on Polarizati

expexpexp

expexpexp

numbersocupation The

states theof Energies

1

1

00

0B field magneticin 12spin with Particles

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Hyperon polarization in presence of magnetic field

radics = 4 -11 GeV

T ~ 100 MeV

part p Λ Σ+ Σ- Ξ0 Ξ- Ω-

|μh By| (MeV)

0091 0019 0077 0037 0039 0020 0064

P () 02 004 015 007 007 004 013

Magnetic Field By asymp 1012 Tesla V Skokov et al ModPhysLett 2009

Nuclear magneton μN = 31510-14 MeVTesla

E=-μh B

Polarization induced by the magnetic field created in HIC is rather small

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Global Hyperon Polarization induced by Orbital Angular Momentum

Large Orbital Angular Momentum

Ly

1052 5

114s energiesNICA

02491576 Re

105 5

200s energies RHIC

Au Au

2 ~

4

5

y

y

NNy

Lfmbat

GeV

CvPhysAbelev

Lfmbat

GeV

bsAL

No evidence for Polarization at RHIC

Proposal

Hyperon Polarization could be

observed at NICA CBM and

BES RHIC

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Orbital Angular Momentum in HIC

2)]2()2([

)( )(

2)]2()2([

NNy

NNz

sybxTybxTxdxdyL

zyxndzyxT

sybxTybxT

dxdy

dp

Ly

A1 A2

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Orbital Angular Momentum vs impact parameter

AuAu-collisions at radics = 9 GeV

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Global orbital angular momentum

Gradient in pz-distribution along the x-direction

x

zimpact

parameter b

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Local Orbital Angular Momentum

x2)(

)(2)(

1

xdxdpxpL

dxdNdxdN

dxdNdxdN

sc

ssbxp

fmx

xpL

dxdydxdy

dpp

zzy

Tpart

Ppart

Tpart

Ppart

z

zy

zz

x

yL

Hydrodynamic analog

non-vanishin local vorticity

ω

Liang amp Wang arXivenucl-th0410079 2004

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Local Orbital Angular Momentum

Au+Au at radics = 9 GeV b = 6 fm

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

bull Particles in the overlap region of two colliding nuclei could be polarized due to the large orbital momentum created in the non-central HIC

bull Proposalbull Hyperon Polarization can be observed at NICA CBM and

BES RHIC bull Why

Hyperon polarization in HIC

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Global Polarization Hyperons in Non-Central HIC

bull Hyperons could be polarized due to the large orbital momentum created in the non-central HIC

bull Preferable (measurable) types of hyperons ndash Λ Ξ- Ω-

bull Λ pπ-

bull Ξ- Λπ-

bull Ω- ΛK- (BR 68)bull Global polarization are measured wrt the reaction planebull Reaction plane is defined by a directed flow

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Measurement of Global Polarization

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Reaction Plane vs Collective Flow Reaction Plane vs Collective Flow

Non-central HIC interaction in overlap region results in a pressure gradient =gt

spatial asymmetry is converted to an asymmetry in momentum space =gt collective flow

x

z

Y

Y

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Definitions Flows

1-st Fourier harmonics v1 rarr directed flow

2-nd Fourier harmonics v2 rarr elliptic flow

))-cos(φ2v +(12πφ Rnsum totN

d

dNψR

v1 = ltcos[(φ ndash Ψr)]gt - direct flow

2vn cos[n(φ ndash Ψr)] - azimuthal asymmetry

v2 = ltcos[2(φ ndash Ψr)]gt - elliptic flow

Ψr - Reaction Plane

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Conclusionbull Enhanced yield of Strangeness at radics ~ 2 divide 10 GeV may be a

manifestation of the nucleon ndash hyperon phase transition in a dense baryonic matter

bull Global hyperon polarization could be preferably detected at this energy range (only)

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Thank you for your attention

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Dileptons Yield

Dileptons are an ideal probe for vector meson spectroscopy in the nuclear medium and for the nuclear

dynamics

p

n

++

p

e+

μ+

e- μ

-

r

no measurements between

2-40 AGeV beam energy yet

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Physics Motivation

bull Are we able to observe unambiguous signals from the most compressed region of the system

bull in-medium modifications of hadrons [ e+e-(μ+μ-)]

Central Au+AuPb+Pb collisions

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

Modelling of in-medium spectral functions for vector mesons

In-medium scenarios

dropping mass collisional broadening dropping mass + coll broad

m=m0(1- 0a r r ) G(Mr)=Gvac(M)+GCB(Mr) m amp GCB(M )r

Collisional width GCB(Mr) ~ g r sVNtot

00 02 04 06 08 10 12 14 16 18 2010-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

dropping mass

A(M

)

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

0 0 1 2 3 5

M [GeVc2]

collisional broadeningA

(M)

-r meson spectral function

00 02 04 06 08 10 12 14 16 18 2010-3

10-2

10-1

100

101

102

M [GeVc2]

0 0 1 2 3 5

dropping mass + collisional broadening

A(M

)

bull Note for a consistent off-shell transport one needs not only in-medium spectral functions but also in-medium transition rates

for all channels with vector mesons ie the full knowledge of the in-medium off-shell cross sections s(sr)

ELB NPA 686 (2001) ELB ampW Cassing NPA 807 (2008) 214

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67

in-medium ρ ndash mass drop (B-R scaling)

radicS = 9 GeV

Hadronic Cocktail

π+π ρ e+

+ e-

+

in-medium ρ ndash width spread

+

+

• On Hyperon Production and Polarization in HIC
• Slide 2
• Does a Phase Transition take place in central Heavy Ion Collisi
• Slide 4
• Space-time Evolution of HIC
• Phase diagram ndash artistrsquos view
• Phase diagram with triple critical point
• Space-time Evolution of HIC (2)
• Space-time Evolution of HIC (3)
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Enhanced yield of K+ in subthreshold kaon production
• Excitation functions of K+π+ K-π- and (Λ+Σ0)π ratios
• Inverse T slopes of K+ and K- spectra
• Is lsquohornrsquo-effect a signal of PT
• Models
• Models (2)
• Models (3)
• Models (4)
• Models (5)
• Models (6)
• Slide 24
• Models (7)
• FAIRndashNICA Energy Range
• Central HIC
• Nucleon Transition into Hyperon Phase
• Slide 29
• Enchancment Mechanism in HIC
• But why lsquohornrsquo structure takes place for K+π+ but not for K-
• Proton Transformations channels
• Neutron Transformations channels
• Higher Collision Energies
• Higher Collision Energies
• Hyperon Resonances Decay
• Stangeness Production in central HIC
• What could be studied in BMampN-NICA-FAIR energy region
• Slide 39
• On Hyperon Polarization in Heavy Ion Collisions
• Slide 41
• Slide 42
• Slide 43
• Production Plane
• Slide 45
• Slide 46
• Global Polarization induced by Magnetic Field created in HIC
• Magnetic Field created in HIC
• Particle polarization in presence
• Hyperon polarization in presence of magnetic field
• Global Hyperon Polarization induced by Orbital Angular Momentum
• Orbital Angular Momentum in HIC
• Orbital Angular Momentum vs impact parameter
• Slide 54
• Slide 55
• Slide 56
• Hyperon polarization in HIC
• Global Polarization Hyperons in Non-Central HIC
• Measurement of Global Polarization
• Reaction Plane vs Collective Flow
• Definitions Flows
• Slide 62
• Thank you for your attention
• Dileptons Yield
• Physics Motivation
• Modelling of in-medium spectral functions for vector mesons
• Slide 67