Chiral Restoration? DCC pion fluctuations… but QCD has more than two flavors

I. DCC with 3 flavors – correlations of Ks0 and K

strange correlations from n DCC “domains”

robust observables, thermal background

II. “conventional” kaon isospin fluctuations

wounded nucleons, HIJING, UrQMD

isospin fluctuations probe models

Strange FluctuationsStrange Fluctuations at RHICat RHIC

Sean Gavin Wayne State University

Strange FluctuationsStrange Fluctuations at RHICat RHIC

Sean Gavin Wayne State University

withwith

J. KapustaJ. Kapusta

withwith

M. Abdel AzizM. Abdel Aziz

Strange Isospin Fluctuations: Why?Strange Isospin Fluctuations: Why?

“2 +1” flavor QCD – transition depends on strange quark masstheory: Pisarski & Wilczek; Gavin, Gocksch & Pisarski; …lattice: Brown et al.; Schmidt, Karsch & Laermann …

SPS + + enhancement explained by many small strange DCC? topological baryon production: Kapusta & Wong; Ellis, Heinz & Kowalski model of chiral symmetry breaking: Kapusta & Srivastava

Kapusta's talkKapusta's talk

Polyakov Loop Condensate model of confinement? many small domains RHIC pT fluctuations: Pisarski & Dumitru K/ enhancement: Scavenius, Dumitru & Lenaghan

consequence:consequence: small strange domains small strange domains kaon fluctuations kaon fluctuations

QCD: chiral symmetry broken by condensate below Tc

condensate for two light flavors:neutral v. charged pion fluctuations

= neutral pion fraction

u, d + strange quark:pion and kaon fluctuations

K = neutral kaon fractionRandrup & Schäffner-Bielich

2+1 flavors 2+1 flavors Kaon Fluctuations? Kaon Fluctuations?

,1)(1 Kf

fK

f

,2

1)(1

ff

dduu ~

,,0

KKKK ,,, 00ssdduu sincos~

Kaon Isospin FluctuationsKaon Isospin Fluctuations

measure Ks0 and charged K+

characterize fluctuations of fK = N0/ Ntot by variance:

single kaon DCC

uncorrelated thermal source

00

00

2

1

2NNN

KKK ss

2

0

00

N

N

N

N

c

cc

3

4124 2

0 Kc f DCCDCC

thermalthermaltotc

statc NNN

411

00

2

0

0

2

0

00 N

N

N

N

N

N

N

N

c

c

c

cc

S.G. & J.Kapusta

Dynamic Isospin FluctuationsDynamic Isospin Fluctuations

experiment: measure Ks0, K+ with different efficiencies

efficiency = measured/observed multiplicities

STAR: 0 ~ 10-20% for Ks0 << c ~ 70% for K+

dynamic isospin fluctuations

robust: independent of efficiencies C. Taylor et al; Pruneau, Gavin and Voloshin

vanishes for thermal sources, uncorrelated sources

nonzero for DCC

0

2

0

0 11

NNN

N

N

N

cc

cdyn

statcdyn 0

Many Small DomainsMany Small Domains

SPS - + + data many domains, size ~ 2 fm Kapusta & Wong

WA98 – no big pion signals resolved model predictions S.G., Gocksch & Pisarski, … n pion domains Amado & Lu; Chow & Cohen

n kaon domains S.G. & Kapusta

Gaussian for n > few

variance

1;)( 111 timesn

Kn f

nff 12122

nc 340

S.G. & J.Kapusta

fraction of DCC kaons

variance

dynamic fluctuations

only DCC contributes

can be positive or negative

ASK:ASK: what about non-equilibrium effects? what about non-equilibrium effects?

DCC + Thermal SourceDCC + Thermal Source

totdyn Nn

1

34

th

thdccc Nn

2222

0

14

3

41

,totdcc NN totth NN 1

totcstatcdyn N400

AA collision – superposition of NN subcollisions

nonequilibrium fluctuations in rapidity interval:NN level – string fragmentation, resonancesAA changes – rescattering, resonance abundance

pp simulations

wounded nucleon model, M participants

““Conventional” Isospin FluctuationsConventional” Isospin Fluctuations

K ( c0 ) ( 0+ ) ( + )

HIJING 0.22 0.03 -0.40 0.04 -2.68 0.03

UrQMD -2.4 0.2 -3.8 0.2 -5.5 0.3

( + )

HIJING -0.50 0.01

UrQMD -0.88 0.02

STAR* -0.302 0.004*preliminary

MNN

dyn

2

Abdel Aziz & S.G.

-0.04

-0.03

-0.02

-0.01

0

0.01

0.02

0.03

0 100 200 300 400

HIJING Dynamical FluctuationsHIJING Dynamical Fluctuations

HIJING simulations for Au+Au at 200 AGeV -0.5 < y < 0.5

Wounded nucleons

ok agreement withwounded nucleon model

dyn different for

MNN

dyn

2

participants, M

dyn

Abdel Aziz & S.G.Kch Ks0

K+ Ks

0

K Ks0

000 ,, sssch KKKKKK

-0.1

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0 50 100 150 200 250 300 350 400

HIJING 0c 0+

UrQMD 0c 0+

Conventional Isospin FluctuationsConventional Isospin Fluctuations

HIJING, UrQMD: Au+Au at 200 AGeV, -0.5 < y < 0.5

similarsimilar charge fluctuationscharge fluctuations

different different isospin fluctuationsisospin fluctuations

-0.02

-0.016

-0.012

-0.008

-0.004

0

BBbarUrQMDHIJING

-0.1

-0.08

-0.06

-0.04

-0.02

0

0 100 200 300 400

dyn

dyn

K+K

+

participants

participants

dynUrQMD HIJING wounded nucleons

different signs for KchKs0

same sign for all centralities

Abdel Aziz & Gavin

-0.016

-0.012

-0.008

-0.004

0

0.004

0 100 200 300 400

10% dcc20% dccwnm

dyn(KsK

+)

DCC from CollisionsDCC from Collisions

threshold for DCC onset

take for b0 ~ 6 fm, 10 DCC, –0.5 < y < 0.5

dynamic fluctuationssensitive to DCC

signal: sign change

compare to not sensitive

200 )/(1)( bbb

220 )1( Bdccdyn

participants

-0.006

-0.004

-0.002

0

0.002

0 100 200 300 400

20% dcc

10% dcc

HIJING

-0.008

-0.006

-0.004

-0.002

0

0.002

HIJING ch HIJING +

URQMD ch URQMD +

Pion Isospin Pion Isospin FluctuationsFluctuations

HIJING, URQMD Au+Au 200 AGeV, -0.5 < y < 0.5

Wounded nucleons

DCC:

photon-photon-fluctuations identify fluctuations identify DCCDCC

no need to reconstruct 0

similar sensitivity to kaons

MNN

dyn

2

participants, M

dyn

dyn 1

4.55dcc

totn N

Summary: Observing Kaon FluctuationsSummary: Observing Kaon Fluctuations

KKss00 K K correlations test 2+1 flavor DCC? correlations test 2+1 flavor DCC? S.G. & Kapusta

SPS data many small strange DCC? Kapusta & Wong small domains from Polyakov loop condensate Pisarski &

Dumitru

Robust observables compare unlike particlesRobust observables compare unlike particles charged particles, baryons Pruneau, Voloshin + S.G. kaon fluctuations

Dynamical isospin observableDynamical isospin observable dynamic fluctuations shows DCC effect distinguishes conventional dynamical models – unlike charge fluctuations

Abdel Aziz + S.G. (in progress)

Multiple Collision Models

robust variance, covariance

depends on subcollision fluctuations

dynamic isospin observable

independent of M

Mcc M

rR

MRRR cccc

00000 2

Mc M

cR 0

222 MMMVM

AA collision – superposition of M nucleon subcollisions

Disoriented Chiral Condensate

nonequilibrium: T drops below Tc transient pion fields condensate field isospin fluctuations

neutral vs. charged pions

2

N

x y

z

yxz i ,0

ff

df

NN

Nf

c

2

1cos

4)(

cos

21

2

0

0

2 flavor QCD, massless u and d quarks -- chiral symmetry above Tc

condensate below Tc breaks symmetry

chiral rotations

ud

uduu

du

5

550

5

~

~

~

dduu ~

5ie

0

0.04

0.08

0.12

0 100 200 300 400

HIJING Au+Au wnm (S+S norm)wnm fit

participants, M

R(K sK+ )

HIJING Covariance

10,000 HIJING events Au+Au at 200 AGeV -0.5 < y < 0.5

Wounded nucleons

HIJING scales like wnm

large contribution frommultiplicity fluctuations

2

22

0

00

M

MM

M

r

NN

CR

c

cc

1

0

MRc