1

Probing quark-gluon matter in ultra-relativistic heavy ion collisions with jet quenching and flow effects

The lecture given at the Xth International School-Seminar  “The Actual Problems of Microworld Physics”, Gomel, Belarus, July 15 - 26, 2009

I.P.Lokhtin

1. Deconfinement of nuclear matter and relativistic heavy ion collisions (SPS RHIC LHC).2. Collective nuclear effects: hydrodymamical flow (low pT) and jet quenching (high pT).3. Monte-Carlo models PYQUEN and HYDJET/HYDJET++.4. Description of the collective nuclear effects at RHIC with HYDJET/HYDJET++ and predictions for LHC. 5. Conclusion.

1

2

Deconfinement of nuclear matter and quark-gluon plasma (QGP) formation – the prediction of Lattice Quantum Chromodynamics (QCD) for systems with high enough

temperature and/or baryon density

Nuclear matter(confinement)

Hadronic matter(confinement)

Quark-Gluon plasma(deconfinement) !

КХД-материя• heating• compressing деконфайнмент и формирование КГП!

3

QGP

4

QCD phase diagram

Tc ~ 160-190 MeV

~ 5 - 10 nuclear density

Quark-Gluon Plasma

Hadron gas

Nuclearmatter

Neutron Star

SPSAGS

Early Universe LHCRHIC

Baryon density

Tem

per

atu

re

c ~ 1 GeV/fm3

~ 10 s after Big Bang

Critical point?

Order of phase transition(Lattice QCD)

high T, low ρ – smooth “crossover”

low T, high ρ – 1-st order transition

Between two extremal states(T(cp)~140-160 МэВ, μв(cp)~350-650 МэВ)

critical point?Non-statistical fluctuations!

energy scan at RHIC (√s=5-50 GeV) and NA61@SPS (Elab=10-158 GeV); new projects CBM@FAIR (GSI) and NICA (JINR)

♥“crossover”

1-st order transtion

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Search of QGP and study of its properties in relativistic heavy ion collisions

The formation of super-dense and hot state of QCD-matter in relativistic heavy ion collisions is possible on large space-time scales

(quasi-macroscopic as compared with characteristic hadronic scales).

Soft probes (pT~ΛQCD=200 MeV) spectra of particles with low

transverse momenta pT , femtoscopic

momentum correlations; flow effects; thermal photons and dileptons; strange particle yield.

Hard probes (pT,M>>ΛQCD=200 MeV) spectra of particles with high transverse

momenta pT , their angular

correlations; hadronic jets; quarkonia (dileptons); heavy quarks (leptons, tagged b-jets).

initial state

pre-equilibrium stage

QGP (hydrodynamics)

hadronization

hadronic stage and “freeze-out”

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7

Main parameters of hot and dense QCD-matter in central collisions Pb+Pb/Au+Au

SPS (CERN) RHIC (BNL) LHC (CERN)

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p + p , Au + Au, d + Au and Cu+Cu at s=20, 62, 130 and 200 GeV

Detectors STAR, PHENIX, PHOBOS, BRAHMS

(provide the data starting from 2000)

Collider RHIC

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10

Low pT: global observables &

nuclear collective effects (perfect QCD fluid at RHIC?)

Strong collective flows: 1) elliptic (in non-central collisions due to transformation of initial spatial anisotropy to final momentum one)

characterized by the coefficient v2=<cos(2φ)> of particles with respect to reaction plane; 2) radial (due to collective transverse expansion) – mass-ordering slope of pT-spectra

Deviation from hydrodynamical behaviour at pT>1.5-2 GeV/c (contribution of hard parton fragmentation is important! viscosity?)

11

The equations of relativistic hydrodynamics for perfect fluid

0,

0.

T

N

, ,n u

5 equations for 5 independent variables

If the equation of state p=p(ε) and initial conditions are known, in principle, the task can be solved (numerically or analytically in some approximations).

Example: famous (1+1)-dimension Bjorken’s scaling

,

.

T u u pP

N nu

P g u u

Tμν – energy-momentum tensor,Nμ – particle number flux through the fluid element μ,uμ – local 4-velocity of the fluid element μ, ε – energy density, n – particle number density,p – pressure.

n(τ) ~ 1/ τ

12

0,

0.

T

N

.

,T u u P p P

N nu P

,, ,, ,n u 9 new variables – the task gets much more complicated!

The equations of relativistic hydrodynamics for viscous fluid

13

vacu

umQ

GP

адроны

q

q

адроныЛидрующая частица

Лидирующая частица

High pT: passing of partonic jets through the hot and dense QCD matter

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Radiative loss(coherent LPM interference)

Gylassy-Wang; BDMPS; GLV; Zakharov; Wiedemann; AdS/CFT,...

Collisional loss (incoherent sum over scatterings)Bjorken; Mrowzinski; Thoma;

Markov; Mustafa et al,...

Medium-induced rescattering and energy loss of hard partons

(«jet quenching»)

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Hard probes: nuclear modification factor

R AA= 1 - for hard processes, incoherent sum of р+р inelastic binary collisions in А+А interactions, NAA =Npp < Ncoll(А,А) >

ddpNdbN

ddpbNdbpR

TNN

coll

TAA

TAA /)(

/)(),,( 2

2

- does not depend on р+р cross section

- differential nuclear modification factor

16

“Jet quenching” at RHIC (Au+Au, Cu+Cu)Agreement with QGP formation, for Au+Au at T0~300-450 MeV and dNg/dy~1100-1500

Strong suppression of hard hadron yield by a factor ~ 5 (scales as Npart instead of Ncoll!) in central collisions (but not for direct photons).

The effect is stronger in central collisions , weaker in peripheral one’s.

The effect decreases with decreasing beam energies and is absent for SPS energies. LHC – stronger suppression of saturation? Up to which pT?

The effects only slightly depends on rapidity.

BRAHMS

1717

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Potential of heavy ion physics at the LHC (Pb+Pb, √s = 4-5.5 A TeV – 2010 year?)

New regime of heavy ion physics with the domination of hard QCD processes in hot and long-lived QGP

complementary measurements from ALICE & CMS/ATLAS

ALICE (low-pТ charged particle tracking, hadron ID, central e and forward μ (J/), γ multiplicity,...) soft probes + selected hard probes

CMS/ATLAS (high-pT charged particle tracking, central μ (J/,Z), hard γ, calorimetric jets...) hard probes + selected soft probes

ATLAS

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New channels for diagnostics of QGP at the LHC Bottomonia (1S), (2S), (3S) - optimal thermometer of QCD-medium (regeneration from QGP to be negligible as compared with charmonia) .

B-physics – energy loss of heavy quarks in QCD-medium (mb>>mc) - direct reconstruction of В-mesons; - semileptonic decays of B-meson pairs; - secondary J/ψ from В-meson decays; - B-jets tagged by energetic muons.

Hadronic jets – energy loss of light partons in QCD-medium, angular distribution of the radiation, various loss mechanisms (up to pT ~ 300 GeV)

- momentum and angular spectra of jets and particles inside jets; - direct measurements of jet fragmentation function with leading charged

hadrons and π0; - medium-modified jet shape; - transverse momentum imbalance in the production processes

γ+jet and γ*/Z(→μ+μ-)+jet.

Monte-Carlo models developed in SINP MSU to simulate jet quenching and flows in HIC

–PYQUEN - medium-induced partonic energy loss model (modifies PYTHIA6.4 jet event), http://cern.ch/lokhtin/pyquen

–HYDJET - merging two independent components: soft hydro-type part and hard multi-parton part generated with PYQUEN, http://cern.ch/lokhtin/hydro/hydjet.html

I. Lokhtin, A. Snigirev, Eur. Phys. J. C 46 (2006) 211

HYDJET reproduces RHIC data on high-pT hadron spectra (bot not so well for low-p

T

hadrons) and can be used for LHC energies. HYDJET/PYQUEN are included in common LHC generator database GENSER and software of most LHC experiments (Latest versions are PYQUEN_1.5 and HYDJET1_6).

HYDJET++ event generator HYDJET++ is the continuation of HYDJET model.

The main routine is written in the object-oriented C++ language under the ROOT environment.

The hard, multi-partonic part of HYDJET++ event is identical to the hard part of Fortran-written HYDJET (PYTHIA6.4xx + PYQUEN1.5) and is included in the generator structure as the separate directory.

The soft part of HYDJET++ event represents the "thermal" hadronic state obtained with the parameterization of freeze-out hypersurface (chemical and thermal freeze-outs are separated) and includes longitudinal, radial and elliptic flow effects and decays of hadronic resonances. The corresponding fast Monte-Carlo simulation procedure (C++ code) FAST MC is adapted.

The different structures of standard (Fortran written) HYDJET and HYDJET++ do not allow one to use both generators by the same way. For hard hadroproduction studies HYDJET is OK. For some soft hadroproduction studies HYDJET++ can be preferable, but new way of implementation in LHC software (GENSER,...) is needed.

First “official” version of HYDJET++ code (HYDJET2.0) and web-page with the documentation has been completed at the end of 2008 (v. 2.1 is about completed): http://cern.ch/lokhtin/hydjet++

The complete manual: I.Lokhtin, L.Malinina, S.Petrushanko, A.Snigirev, I.Arsene, K.Tywoniuk, Computing Physics Communications 180 (2009) 779.

Medium-induced partonic energy loss in PYQUEN

General kinetic integral equation:

1. Collisional loss and elastic scattering cross section:

2. Radiative loss (BDMS):

“dead cone” approximation for massive quarks:

E L , E0

L

dxdPdx

x xdEdx

x , E ,dPdx

x1x

exp x x

dEdx

m q 02 s C F

L E LPM g D2

E

d 1 yy 2

2ln cos 1 1 , 1 i 1 y

C F

3y 2 k ln

16k

, k D2

g

1 y, 1

L

2 g

, yE

, C F

43

dEdx

m q 01

1 l 3 2 2

dEdx

m q 0 , lD2

1 3 m q

E

4 3

dEdx

14T

D2

t max

dtddt

t ,ddt

C2 s

2 t

t 2, S

12

33 2N f ln t QCD2

, C 9 4 gg , 1 gq , 4 9 qq

__ __ __ ____

____ ___ __ ________

__ ____ __ __ __ __ __ __

__ __ __ _________

______________

____

Angular spectrum of gluon radiation

Three option for angular distribution of in-medium emitted gluons:

Collinear radiation

Small-angular radiation (default)

Broad-angular radiation

dN g

dsin exp 0

2

2 02

, 0 5 o

d N g

d1

0

Nuclear geometry and QGP evolution

impact parameter b≡ |O1O

2| - transverse distance between nucleus centers

Space-time evolution of QGP, created in region of initial overlaping of colliding nuclei, is descibed by Lorenz-invariant Bjorken's hydrodynamics J.D. Bjorken, PRD 27 (1983) 140

ε(r1,r

2) ~ T

A(r

1) ∗ T

A(r

2) (T

A(b) - nuclear thickness function)

Monte-Carlo simulation of parton rescattering and energy loss in PYQUEN– Distribution over jet production vertex V(r cosψ, r sinψ) at im.p. b

– Transverse distance between parton scatterings li=(τ

i+1- τ

i) E/p

T

– Radiative and collisional energy loss per scattering

– Transverse momentum kick per scattering

dNd dr

bT A r1 T A r 2

0

2

d0

r max

rdrT A r1 T A r 2

dPdl i

1i 1 exp

0

l i

1i s ds , 1

E tot , i E rad , i E col , i

kt , i

2 Et

i

2m 0i

2

pEp

ti

2m 0i

ti

2p

2

mq

2

____ __________________

PYQUEN (PYthia QUENched)

Initial parton configuration PYTHIA6.4 w/o hadronization: mstp(111)=0

Parton hadronization and final particle formation PYTHIA6.4 with hadronization: call PYEXEC

↓

↓

Parton rescattering & energy loss (collisional, radiative) + emitted g PYQUEN rearranges partons to update ns strings: ns call PYJOIN

Three model parameters: initial QGP temperature T0, QGP formation time τ

0 and

number of active quark flavors in QGP Nf (in central Pb+Pb)

(+ minimal pT of hard process Ptmin and other PYTHIA parameters)

HYDJET & HYDJET++ (HYDrodynamics + JETs)

–Calculating the number of hard NN sub-collisions Njet (b, Ptmin, √s) with Pt>Ptmin around its mean value according to the binomial distribution. –Selecting the type (for each of Njet) of hard NN sub-collisions (pp, np or nn) depending on number of protons (Z) and neutrons (A-Z) in nucleus A according to the formula: Z=A/(1.98+0.015A2/3)–Generating the hard part by calling PYTHIA/PYQUEN njet times–If nuclear shadowing is switched on, the correction for PDF in nucleus is done by the accepting/rejecting procedure for each of Njet hard NN sub-collisions: by comparision of random number generated uniformly in the interval [0,1] with shadowing factor S ≤ 1, which is taken from the adapted impact parameter dependent parameterization based on Glauber-Gribov theory (K.Tywoniuk et al.,, Phys. Lett. B 657 (2007) 170).–Generating the soft part according to the corresponding “thermal” model (for b≠0 mean multiplicty is proportional to # of N-participants) –Junction of two independent event outputs (hard & soft) to event record

HYDJET: simple (but fast) model for soft hadroproduction

The final hadron spectrum (π, K, p) are given by the superposition of thermal distribution and collective flow assuming Bjorken's scaling. 1. Thermal distribution of produced hadron in rest frame of fluid element

2. Space position r and local 4-velocity uμ

3. Boost of hadron 4-momentum pμ

in c.m. frame of the event

f E 0 E 0 E 02 m 2 exp E 0 T f , 1 cos 0 1, 0 0 2

f r 2r R f

2R A , b , 0 r R f , f e

Y Lmax 2

2 Y Lmax 2

, 0 2

u r sinh Y Tmax r R eff R A , b R A , u t 1 u r

2 cosh , u z 1 u r2 sinh

p x p 0 sin 0 cos 0 u r cos E 0 u i p 0i u t 1 ,

p y p 0 sin 0 sin 0 u r sin E 0 u i p 0i u t 1 ,

p z p 0 cos 0 u z E 0 u i p 0i u t 1 ,

E E 0 u t u i p 0i , u i p 0

i u r p 0 sin 0 cos 0 u z p 0 cos 0

HYDJET: model parameters External input

– beam and target nucleus atomic weight (A=B) – c.m.s. energy per nucleon pair – impact parameter (fixed or distributed) – total mean multiplicity of soft part in central Pb+Pb events (multiplicity for other

centralities and atomic weights is calculated automatically)

Parameter can be varied by user – ytfl - maximum transverse collective rapidity, controls slope of low-pt spectra

(0.01<ytfl<3.0, default value is ytfl=1.5)– ylfl - maximum longitudinal collective rapidity, controls width of η-spectra

(0.01<ylfl<7.0, default value is ylfl=4.)– Tf – hadron freeze-out temperature (0.08 <Tf < 0.2, Tf(default)=0.1 GeV)– fpart - fraction of multiplicity proportional to # of participants;

(1.-fpart) - fraction of multiplicity proportional to # of NN subcollisions (0.0<fpart<1.0, default value is fpart=1.)

– some parameters and flags of parton energy loss model PYQUEN– flags to switch on/off jet production, jet quenching and nuclear shadowing – ptmin=ckin(3) - minimal pT of parton-parton scattering in PYTHIA

Internal sets for soft part– poison multiplicty distribution – thermal particle ratios (π, K and p only)

HYDJET: output information

Output particle information: – event record in PYTHIA/JETSET format

(common block HYJETS, #150000)

Output global event characteristics: – bgen - generated value of impact parameter – nbcol - mean # of NN subcollisions at given bgen – npart - mean # of nucleon participants at given bgen – npyt - multiplicity of jet-induced particles in the event – nhyd - multiplicity of HYDRO-induced particles in the event – njet - number of hard parton-parton scatterings with pt>ptmin in event – sigin - total inelastic NN cross section at given c.m.s. energy– sigjet - hard scattering NN cross section at given ptmin and energy

HYDJET++: more detailed (and still fast) model for soft hadroproduction

– fast (but realistic) HYDJET-inspired MC procedure for soft hadron generation

– multiplicities are determined assuming thermal equilibrium – hadrons are produced on the hypersurface represented by a parameterization of relativistic hydrodynamics with given freeze-out conditions – chemical and kinetic freeze-outs are separated – decays of hadronic resonances are taken into account (360 particles from SHARE

data table) with “home-made'' decayer – written within ROOT framework (C++)– contains 15 free parameters (but this number may be reduced to 9)

Soft (hydro) part of HYDJET++ is based on the adapted FAST MC model: Part I: N.S.Amelin, R.Lednisky, T.A.Pocheptsov, I.P.Lokhtin, L.V.Malinina, A.M.Snigirev, Yu.A.Karpenko, Yu.M.Sinyukov, Phys. Rev. C 74 (2006) 064901 Part II: N.S.Amelin, R.Lednisky, I.P.Lokhtin, L.V.Malinina, A.M.Snigirev, Yu.A.Karpenko, Yu.M.Sinyukov, I.C.Arsene, L.Bravina, Phys. Rev. C 77 (2008) 014903

HYDJET++ (soft): main physics assumptions

A hydrodynamic expansion of the fireball is supposed ends by a sudden system

breakup at given T and chemical potentials. Momentum distribution of produced

hadrons keeps the thermal character of the equilibrium distribution.

Cooper-Frye formula:

- FAST MC avoids straightforward 6-dimensional integration by using the special

simulation procedure (like HYDJET): momentum generation in the rest frame of fluid

element, then Lorentz transformation in the global frame → uniform weights →

effective von-Neumann rejection-acception procedure.

-

),);(()()(

33

30

i

x

eqi

i Txupfpxdpd

Ndp

Freeze-out surface parameterizations1. The Bjorken model with hypersurface

2. Linear transverse flow rapidity profile

3. The total effective volume for particle production at

constzt 2/122 )(maxuu R

r

)1coshsinh(2)()( maxmaxmax

2

max

2

00)(

3max

min

uuu

u

R

r

x

eff

RddrdrxuxdV

HYDJET++ (soft): hadron multiplicities

1. The hadronic matter created in heavy-ion collisions is considered as a hydrodynamically expanding fireball with EOS of an ideal hadron gas.

2. “Concept of effective volume” T=const and µ=const: the total yield of particle species is .

3. Chemical freeze-out : T, µi = µB Bi + µS Si + µc Ci +µQ Qi ; T, µB –can be fixed by particle ratios, or by phenomenological formulas

4. Chemical freeze-out: all macroscopic characteristics of particle system are determined via a set of equilibrium distribution functions in the fluid element rest frame:

effiii VTN ),(

NN

NNBBBBse

dscbaT

1)(;)( 4

1)/]exp([)2(1

),;( *03*0

Tpg

Tpfi

ii

eqi

),;(4))(),(;(),( *02*

0

****0

0

*3i

eqii

eqii

eqi TpfpdpxxTpfpdT

HYDJET++ (soft): thermal and chemical freeze-outs

1. The particle densities at the chemical freeze-out stage are too high to consider particles as free streaming and to associate this stage with the thermal freeze-out

2. Within the concept of chemically frozen evolution, assumption of the conservation of the particle number ratios from the chemical to thermal freeze-out :

3. The absolute values are determined by the choice of the free parameter of the model: effective pion chemical potential at Assuming for the other particles (heavier then pions) the Botzmann approximation :

Particles (stable, resonances) are generated on the thermal freeze-out hypersurface, the hadronic

composition at this stage is defined by the parameters of the system at chemical freeze-out

),(

),(

),(

),(ththeq

thi

theqi

chcheq

chi

cheqi

T

T

T

T

),( thi

theqi T

theff , thT

),(),(

)0,(),(

ln,

chi

cheq

thefftheq

itheq

i

chi

cheqithth

i TT

TT

T

Thermal charmed mesons J/ψ, D0, D0, D+, D- , Ds+, D

s-, Λc

+, Λc-

are generated within the statistical hadronization model(feed-down corrections and meson 2- and 3- body decays are performed)

ND=γ

cN

Dth(I

1(γ

cN

Dth)/I

0(γ

cN

Dth)), N

J/ψ=γc2 N

J/ψth

γc - charm enhancement factor obtained from the equation:

Ncc

=0.5γcN

Dth(I

1(γ

cN

Dth)/I

0(γ

cN

Dth))+γ

c2 N

J/ψth

where number of c-quark pairs Ncc

is calculated with PYTHIA (the factor K=2 is applied to take into account NLO pQCD corrections)

HYDJET++ (soft, from version 2.1): thermal charm production

-

HYDJET++ (soft): input parameters

1-5. Thermodynamic parameters at chemical freeze-out: Tch , {µ

B, µ

S, µ

C,µ

Q}

(option to calculate Tch, µB and µ

s using phenomenological parameterization µ

B(√s),

Tch( µB) is foreseen).

6. Strangeness suppression factor γS ≤ 1 (the option to use phenomenological

parameterization γS (Tch, µ

B) is foreseen).

7-8. Thermodynamical parameters at thermal freeze-out: Tth , and µπ- effective chemical

potential of positively charged pions.

9-11. Volume parameters at thermal freeze-out: proper time τf , its standard deviation

(emission duration) Δτf , maximal transverse radius R

f .

12. Maximal transverse flow rapidity at thermal freeze-out ρu

max .

13. Maximal longitudinal flow rapidity at thermal freeze-out ηmax .

14. Flow anisotropy parameter: δ(b) → uμ = uμ (δ(b),φ)

15. Coordinate anisotropy: ε(b) → Rf(b)=Rf(0)[Veff(ε(0),δ(0))/Veff(ε(b),δ(b))]1/2[Npart(b)/Npart(0)]1/3

Impact parameter range: (bmin, bmax):

Veff(b)=Veff(0)Npart(b)/Npart(0),

τf(b)=τf(0)[Npart(b)/Npart(0)]1/3

The block structure of HYDJET++

particles.data,tabledecay.txt (particle properties)

RunInputHydjet(input model parameters)

RunOutput.root (particle output information for each event and global output parameters)

RunHadronSource.cxx(generate events, create trees)

Tree “td” (final particle output)

ROOT

Histograms

ROOT macros (to produce histograms)

Number of events to generate10 C.m.s. energy per nucleon pair, fSqrtS [GeV]200. Atomic weigth of nuclei, fAw197. Flag of type of centrality generation, fBfix (=0 is fixed by fBfix, >0 distributed [fBfmin, fBmax])1 Minimum impact parameter in units of nuclear radius, fBmin0. Maximum impact parameter in units of nuclear radius, fBmax0.55 Fixed impact parameter in units of nuclear radius, fBfix0. Parameter to set random number seed, fSeed (=0 the current time is used, >0 the value fSeed is used) 0 Temperature at chemical freeze-out, fT [GeV]0.165 Chemical baryon potential per unit charge, fMuB [GeV]0.0285 Chemical strangeness potential per unit charge, fMuS [GeV] 0.007 Chemical charm potential per unit charge, fMuC [GeV] (used if charm production is turned on) 0. Chemical isospin potential per unit charge, fMuI3 [GeV] -0.001 Temperature at thermal freeze-out, fTthFO [GeV]0.1 Chemical potential of pi+ at thermal freeze-out, fMu_th_pip [GeV] 0.06 Proper time proper at thermal freeze-out for central collisions, fTau [fm/c]8. Duration of emission at thermal freeze-out for central collisions, fSigmaTau [fm/c]2. Maximal transverse radius at thermal freeze-out for central collisions, fR [fm]10. Maximal longitudinal flow rapidity at thermal freeze-out, fYlmax3.3 Maximal transverse flow rapidity at thermal freeze-out for central collisions, fUmax1.1 Momentum azimuthal anizotropy parameter at thermal freeze-out, fDelta0.1 Spatial azimuthal anisotropy parameter at thermal freeze-out, fEpsilon0.05 Flag to specify fDelta and fEpsilon values, fIfDeltaEpsilon (=0 user's ones, >=1 calculated) 0. Flag to switch on/off hadron decays, fDecay (=0 decays off, >=1 decays on)1. Low decay width threshold fWeakDecay[GeV]: width<fWeakDecay decay off, width>=fDecayWidth decay on; can be used to switch off weak decays0. Flag to choose rapidity distribution, fEtaType (=0 uniform, >0 Gaussian with the dispersion Ylmax)1. Flag to use calculated T_ch, mu_B and mu_S as a function of fSqrtS, fTMuType (=0 user's ones, >0 calculated) 0. Strangeness supression factor gamma_s with fCorrS value (0<fCorrS <=1, if fCorrS <= 0., then it will be calculated) 1. Flag to include statistical charm productio, fIcharm (=0 no charm production, >=1 charm production) 0 Flag to include jets (J)/jet quenching (JQ) and hydro (H) , fNhsel (0 H on & J off, 1 H/J on & JQ off, 2 H/J/HQ on, 3 J on & H/JQ off, 4 H off & J/JQ on)2 Flag to suppress the output of particle history from PYTHIA, fIedit (=1 only final state particles; =0 full particle history from PYTHIA)1 Flag to switch on/off nuclear shadowing, fIshad (0 shadowing off, 1 shadowing on)1 Minimal pt of parton-parton scattering in PYTHIA event, fPtmin [GeV/c] 3.4 Initial QGP temperature for central Pb+Pb collisions in mid-rapidity, fT0 [GeV] 0.3 Proper QGP formation time in fm/c, fTau0 (0.01<fTau0<10)0.4 Number of active quark flavours in QGP, fNf (0, 1, 2 or 3)2 Flag to fix type of partonic energy loss, fIenglu (0 radiative and collisional loss, 1 radiative loss only, 2 collisional loss only)0 Flag to fix type of angular distribution of in-medium emitted gluons, fIanglu (0 small-angular, 1 wide-angular, 2 collinear).0

Number of events to generate10 C.m.s. energy per nucleon pair, fSqrtS [GeV]200. Atomic weigth of nuclei, fAw197. Flag of type of centrality generation, fBfix (=0 is fixed by fBfix, >0 distributed [fBfmin, fBmax])1 Minimum impact parameter in units of nuclear radius, fBmin0. Maximum impact parameter in units of nuclear radius, fBmax0.55 Fixed impact parameter in units of nuclear radius, fBfix0. Parameter to set random number seed, fSeed (=0 the current time is used, >0 the value fSeed is used) 0 Temperature at chemical freeze-out, fT [GeV]0.165 Chemical baryon potential per unit charge, fMuB [GeV]0.0285 Chemical strangeness potential per unit charge, fMuS [GeV] 0.007 Chemical charm potential per unit charge, fMuC [GeV] (used if charm production is turned on) 0. Chemical isospin potential per unit charge, fMuI3 [GeV] -0.001 Temperature at thermal freeze-out, fTthFO [GeV]0.1 Chemical potential of pi+ at thermal freeze-out, fMu_th_pip [GeV] 0.06 Proper time proper at thermal freeze-out for central collisions, fTau [fm/c]8. Duration of emission at thermal freeze-out for central collisions, fSigmaTau [fm/c]2. Maximal transverse radius at thermal freeze-out for central collisions, fR [fm]10. Maximal longitudinal flow rapidity at thermal freeze-out, fYlmax3.3 Maximal transverse flow rapidity at thermal freeze-out for central collisions, fUmax1.1 Momentum azimuthal anizotropy parameter at thermal freeze-out, fDelta0.1 Spatial azimuthal anisotropy parameter at thermal freeze-out, fEpsilon0.05 Flag to specify fDelta and fEpsilon values, fIfDeltaEpsilon (=0 user's ones, >=1 calculated) 0. Flag to switch on/off hadron decays, fDecay (=0 decays off, >=1 decays on)1. Low decay width threshold fWeakDecay[GeV]: width<fWeakDecay decay off, width>=fDecayWidth decay on; can be used to switch off weak decays0. Flag to choose rapidity distribution, fEtaType (=0 uniform, >0 Gaussian with the dispersion Ylmax)1. Flag to use calculated T_ch, mu_B and mu_S as a function of fSqrtS, fTMuType (=0 user's ones, >0 calculated) 0. Strangeness supression factor gamma_s with fCorrS value (0<fCorrS <=1, if fCorrS <= 0., then it will be calculated) 1. Flag to include statistical charm productio, fIcharm (=0 no charm production, >=1 charm production) 0 Flag to include jets (J)/jet quenching (JQ) and hydro (H) , fNhsel (0 H on & J off, 1 H/J on & JQ off, 2 H/J/HQ on, 3 J on & H/JQ off, 4 H off & J/JQ on)2 Flag to suppress the output of particle history from PYTHIA, fIedit (=1 only final state particles; =0 full particle history from PYTHIA)1 Flag to switch on/off nuclear shadowing, fIshad (0 shadowing off, 1 shadowing on)1 Minimal pt of parton-parton scattering in PYTHIA event, fPtmin [GeV/c] 3.4 Initial QGP temperature for central Pb+Pb collisions in mid-rapidity, fT0 [GeV] 0.3 Proper QGP formation time in fm/c, fTau0 (0.01<fTau0<10)0.4 Number of active quark flavours in QGP, fNf (0, 1, 2 or 3)2 Flag to fix type of partonic energy loss, fIenglu (0 radiative and collisional loss, 1 radiative loss only, 2 collisional loss only)0 Flag to fix type of angular distribution of in-medium emitted gluons, fIanglu (0 small-angular, 1 wide-angular, 2 collinear).0

RunInputHydjetRHIC200(input parameter file for Au+Au collisions at RHIC, default)

7 input parameters;19 free model parameters(may be reduced to 13) + PYTHIA parameters; 12 flags.

Number of events to generate10 C.m.s. energy per nucleon pair, fSqrtS [GeV]5500. Atomic weigth of nuclei, fAw207. Flag of type of centrality generation, fBfix (=0 is fixed by fBfix, >0 distributed [fBfmin, fBmax])1 Minimum impact parameter in units of nuclear radius, fBmin0. Maximum impact parameter in units of nuclear radius, fBmax0.57 Fixed impact parameter in units of nuclear radius, fBfix0. Parameter to set random number seed, fSeed (=0 the current time is used, >0 the value fSeed is used) 0 Temperature at chemical freeze-out, fT [GeV]0.170 Chemical baryon potential per unit charge, fMuB [GeV]0. Chemical strangeness potential per unit charge, fMuS [GeV] 0. Chemical charm potential per unit charge, fMuC [GeV] (used if charm production is turned on) 0. Chemical isospin potential per unit charge, fMuI3 [GeV] 0. Temperature at thermal freeze-out, fTthFO [GeV]0.13 Chemical potential of pi+ at thermal freeze-out, fMu_th_pip [GeV] 0. Proper time proper at thermal freeze-out for central collisions, fTau [fm/c]10. Duration of emission at thermal freeze-out for central collisions, fSigmaTau [fm/c]3. Maximal transverse radius at thermal freeze-out for central collisions, fR [fm]11. Maximal longitudinal flow rapidity at thermal freeze-out, fYlmax4. Maximal transverse flow rapidity at thermal freeze-out for central collisions, fUmax1.1 Momentum azimuthal anizotropy parameter at thermal freeze-out, fDelta0.1 Spatial azimuthal anisotropy parameter at thermal freeze-out, fEpsilon0.05 Flag to specify fDelta and fEpsilon values, fIfDeltaEpsilon (=0 user's ones, >=1 calculated) 0. Flag to switch on/off hadron decays, fDecay (=0 decays off, >=1 decays on)1. Low decay width threshold fWeakDecay[GeV]: width<fWeakDecay decay off, width>=fDecayWidth decay on; can be used to switch off weak decays0. Flag to choose rapidity distribution, fEtaType (=0 uniform, >0 Gaussian with the dispersion Ylmax)1. Flag to use calculated T_ch, mu_B and mu_S as a function of fSqrtS, fTMuType (=0 user's ones, >0 calculated) 0. Strangeness supression factor gamma_s with fCorrS value (0<fCorrS <=1, if fCorrS <= 0., then it will be calculated) 1. Flag to include thermal charm production, fIcharm (=0 no charm production, >=1 charm production) 0. Flag to include jets (J)/jet quenching (JQ) and hydro (H), fNhsel (0 H on & J off, 1 H/J on & JQ off, 2 H/J/HQ on, 3 J on & H/JQ off, 4 H off & J/JQ on)2 Flag to suppress the output of particle history from PYTHIA, fIedit (=1 only final state particles; =0 full particle history from PYTHIA)1 Flag to switch on/off nuclear shadowing, fIshad (0 shadowing off, 1 shadowing on)1 Minimal pt of parton-parton scattering in PYTHIA event, fPtmin [GeV/c] 7. Initial QGP temperature for central Pb+Pb collisions in mid-rapidity, fT0 [GeV] 0.8 Proper QGP formation time in fm/c, fTau0 (0.01<fTau0<10)0.1 Number of active quark flavours in QGP, fNf (0, 1, 2 or 3)0 Flag to fixe type of partonic energy loss, fIenglu (0 radiative and collisional loss, 1 radiative loss only, 2 collisional loss only)0 Flag to fix type of angular distribution of in-medium emitted gluons, fIanglu (0 small-angular, 1 wide-angular, 2 collinear).0

Number of events to generate10 C.m.s. energy per nucleon pair, fSqrtS [GeV]5500. Atomic weigth of nuclei, fAw207. Flag of type of centrality generation, fBfix (=0 is fixed by fBfix, >0 distributed [fBfmin, fBmax])1 Minimum impact parameter in units of nuclear radius, fBmin0. Maximum impact parameter in units of nuclear radius, fBmax0.57 Fixed impact parameter in units of nuclear radius, fBfix0. Parameter to set random number seed, fSeed (=0 the current time is used, >0 the value fSeed is used) 0 Temperature at chemical freeze-out, fT [GeV]0.170 Chemical baryon potential per unit charge, fMuB [GeV]0. Chemical strangeness potential per unit charge, fMuS [GeV] 0. Chemical charm potential per unit charge, fMuC [GeV] (used if charm production is turned on) 0. Chemical isospin potential per unit charge, fMuI3 [GeV] 0. Temperature at thermal freeze-out, fTthFO [GeV]0.13 Chemical potential of pi+ at thermal freeze-out, fMu_th_pip [GeV] 0. Proper time proper at thermal freeze-out for central collisions, fTau [fm/c]10. Duration of emission at thermal freeze-out for central collisions, fSigmaTau [fm/c]3. Maximal transverse radius at thermal freeze-out for central collisions, fR [fm]11. Maximal longitudinal flow rapidity at thermal freeze-out, fYlmax4. Maximal transverse flow rapidity at thermal freeze-out for central collisions, fUmax1.1 Momentum azimuthal anizotropy parameter at thermal freeze-out, fDelta0.1 Spatial azimuthal anisotropy parameter at thermal freeze-out, fEpsilon0.05 Flag to specify fDelta and fEpsilon values, fIfDeltaEpsilon (=0 user's ones, >=1 calculated) 0. Flag to switch on/off hadron decays, fDecay (=0 decays off, >=1 decays on)1. Low decay width threshold fWeakDecay[GeV]: width<fWeakDecay decay off, width>=fDecayWidth decay on; can be used to switch off weak decays0. Flag to choose rapidity distribution, fEtaType (=0 uniform, >0 Gaussian with the dispersion Ylmax)1. Flag to use calculated T_ch, mu_B and mu_S as a function of fSqrtS, fTMuType (=0 user's ones, >0 calculated) 0. Strangeness supression factor gamma_s with fCorrS value (0<fCorrS <=1, if fCorrS <= 0., then it will be calculated) 1. Flag to include thermal charm production, fIcharm (=0 no charm production, >=1 charm production) 0. Flag to include jets (J)/jet quenching (JQ) and hydro (H), fNhsel (0 H on & J off, 1 H/J on & JQ off, 2 H/J/HQ on, 3 J on & H/JQ off, 4 H off & J/JQ on)2 Flag to suppress the output of particle history from PYTHIA, fIedit (=1 only final state particles; =0 full particle history from PYTHIA)1 Flag to switch on/off nuclear shadowing, fIshad (0 shadowing off, 1 shadowing on)1 Minimal pt of parton-parton scattering in PYTHIA event, fPtmin [GeV/c] 7. Initial QGP temperature for central Pb+Pb collisions in mid-rapidity, fT0 [GeV] 0.8 Proper QGP formation time in fm/c, fTau0 (0.01<fTau0<10)0.1 Number of active quark flavours in QGP, fNf (0, 1, 2 or 3)0 Flag to fixe type of partonic energy loss, fIenglu (0 radiative and collisional loss, 1 radiative loss only, 2 collisional loss only)0 Flag to fix type of angular distribution of in-medium emitted gluons, fIanglu (0 small-angular, 1 wide-angular, 2 collinear).0

RunInputHydjetLHC5500(input parameter file for Pb+Pb collisions at LHC, default)

7 input parameters;19 free model parameters(may be reduced to 13) + PYTHIA parameters; 12 flags.

td->Branch("nev",&nev,"nev/I"); // event number td->Branch("Bgen",&Bgen,"Bgen/F"); // generated impact parameter td->Branch("Sigin",&Sigin,"Sigin/F"); // total inelastic NN cross section td->Branch("Sigjet",&Sigjet,"Sigjet/F"); // hard scattering NN cross section td->Branch("Ntot",&Ntot,"Ntot/I"); // total event multiplicity td->Branch("Nhyd",&Nhyd,"Nhyd/I"); // multiplicity of hydro-induced particles td->Branch("Npyt",&Npyt,"Npyt/I"); // multiplicity of jet-induced particles td->Branch("Njet",&Njet,"Njet/I"); // number of hard parton-parton scatterings td->Branch("Nbcol",&Nbcol,"Nbcol/I"); // mean number of NN sub-collisions td->Branch("Npart",&Npart,"Npart/I"); // mean number of nucleon-participants td->Branch("Px",&Px[0],"Px[npart]/F"); // x-component of the momentum, in GeV/c td->Branch("Py",&Py[0],"Py[npart]/F"); // y-component of the momentum, in GeV/c td->Branch("Pz",&Pz[0],"Pz[npart]/F"); // z-component of the momentum, in GeV/c td->Branch("E",&E[0],"E[npart]/F"); // energy, in GeV td->Branch("X",&X[0],"X[npart]/F"); // x-coordinate at emission point, in fm td->Branch("Y",&Y[0],"Y[npart]/F"); // y-coordinate at emission point, in fm td->Branch("Z",&Z[0],"Z[npart]/F"); // z-coordinate at emission point, in fm td->Branch("T",&T[0],"T[npart]/F"); // proper time of particle emission, in fm/c td->Branch("pdg",&pdg[0],"pdg[npart]/I"); // Geant particle code td->Branch("Mpdg",&Mpdg[0],"Mpdg[npart]/I"); // Geant code of mothers (-1 for primordials) td->Branch("type",&type[0],"type[npart]/I") // particle origin (=0 – from hydro, >0 – jets) td->Branch("Index",&Index[0],"Index[Ntot]/I"); // unique zero based index of the particle td->Branch("MotherIndex",&MotherIndex[0],"MotherIndex[Ntot]/I"); // index of mother (-1 for primordials) td->Branch("NDaughters",&NDaughters[0],"NDaughters[Ntot]/I"); // number of daughters td->Branch("FirstDaughterIndex",&FirstDaughterIndex[0],"FirstDaughterIndex[Ntot]/I"); // index of 1st daughter

td->Branch("LastDaughterIndex",&LastDaughterIndex[0],"LastDaughterIndex[Ntot]/I"); // index of last daughter

td->Branch("pythiaStatus",&pythiaStatus[0],"pythiaStatus[Ntot]/I"); // PYTHIA status code (-1 for hydro) td->Branch("final",&final[0],"final[Ntot]/I"); // an integer branch: =1 for final particles, =0 for decayed

td->Branch("nev",&nev,"nev/I"); // event number td->Branch("Bgen",&Bgen,"Bgen/F"); // generated impact parameter td->Branch("Sigin",&Sigin,"Sigin/F"); // total inelastic NN cross section td->Branch("Sigjet",&Sigjet,"Sigjet/F"); // hard scattering NN cross section td->Branch("Ntot",&Ntot,"Ntot/I"); // total event multiplicity td->Branch("Nhyd",&Nhyd,"Nhyd/I"); // multiplicity of hydro-induced particles td->Branch("Npyt",&Npyt,"Npyt/I"); // multiplicity of jet-induced particles td->Branch("Njet",&Njet,"Njet/I"); // number of hard parton-parton scatterings td->Branch("Nbcol",&Nbcol,"Nbcol/I"); // mean number of NN sub-collisions td->Branch("Npart",&Npart,"Npart/I"); // mean number of nucleon-participants td->Branch("Px",&Px[0],"Px[npart]/F"); // x-component of the momentum, in GeV/c td->Branch("Py",&Py[0],"Py[npart]/F"); // y-component of the momentum, in GeV/c td->Branch("Pz",&Pz[0],"Pz[npart]/F"); // z-component of the momentum, in GeV/c td->Branch("E",&E[0],"E[npart]/F"); // energy, in GeV td->Branch("X",&X[0],"X[npart]/F"); // x-coordinate at emission point, in fm td->Branch("Y",&Y[0],"Y[npart]/F"); // y-coordinate at emission point, in fm td->Branch("Z",&Z[0],"Z[npart]/F"); // z-coordinate at emission point, in fm td->Branch("T",&T[0],"T[npart]/F"); // proper time of particle emission, in fm/c td->Branch("pdg",&pdg[0],"pdg[npart]/I"); // Geant particle code td->Branch("Mpdg",&Mpdg[0],"Mpdg[npart]/I"); // Geant code of mothers (-1 for primordials) td->Branch("type",&type[0],"type[npart]/I") // particle origin (=0 – from hydro, >0 – jets) td->Branch("Index",&Index[0],"Index[Ntot]/I"); // unique zero based index of the particle td->Branch("MotherIndex",&MotherIndex[0],"MotherIndex[Ntot]/I"); // index of mother (-1 for primordials) td->Branch("NDaughters",&NDaughters[0],"NDaughters[Ntot]/I"); // number of daughters td->Branch("FirstDaughterIndex",&FirstDaughterIndex[0],"FirstDaughterIndex[Ntot]/I"); // index of 1st daughter

td->Branch("LastDaughterIndex",&LastDaughterIndex[0],"LastDaughterIndex[Ntot]/I"); // index of last daughter

td->Branch("pythiaStatus",&pythiaStatus[0],"pythiaStatus[Ntot]/I"); // PYTHIA status code (-1 for hydro) td->Branch("final",&final[0],"final[Ntot]/I"); // an integer branch: =1 for final particles, =0 for decayed

RunOutput.root(tree structure)

HYDJET++ : particle ratios at RHIC

Particle number ratios near mid-rapidity in central Au Au collisions

Tch=0.165 GeV µB=0.028, µ

S=0.007,

µQ=-0.001GeV

Tth=0.100, 0.130, 0.165 GeV

HYDJET++: radial flow at RHIC

ρu

max =1.1

HYDJET++: elliptic flow at RHIC ...)4cos22cos1(

2 422

vv

dydpp

dN

dypd

dN

ttt

HYDJET++: momentum correlations (HBT-radii) at RHIC

)2exp(1),( 2,

22222221 longoutlongoutlonglongsidesideoutout qqRqRqRqRppCF

τf = 8 fm/c, Δτ

f =2 fm/c, R

f =10 fm

HYDJET++: rapidity spectra vs. event centrality at RHIC

Width of the spectra allows one to fix ηmax =3.3, Centrality dependence of multiplicity allows one to fix ptmin=3.4 GeV/c and μ

π=0.06

HYDJET++: transverse momentum spectra at RHIC (high-p

T)

PYQUEN energy loss model parameters: T0(QGP)=300 MeV, τ

0(QGP)=0.4 fm/c, N

f=2

HYDJET++: hadron spectra at LHC

1000 events Pb+Pb (0-5 % centrality) at √s=5.5 A TeV (default parameters, ptmin=7 GeV/c)

HYDJET++: hadron spectra at LHC

1000 events Pb+Pb (0-5 % centrality) at √s=5.5 A TeV (default parameters, ptmin=10 GeV/c)

Influence of jet fragmentation on correlation radii at LHC

STAR

HYDJET++, ptmin>7 GeV/c

HYDJET++, ptmin>10 GeV/c

HYDJET++, hydro only

Pure hydro (no jets):R(LHC) > R(RHIC)Ptmin=10 GeV/c(~25% jet contribution): R(LHC) ~ R(RHIC)Ptmin=7 GeV/c(~55% jet contribution): R(LHC) < R(RHIC)! (especially Rlong)

due to the significant influence of “jet-induced” hadrons, which are emitted on shorter space-time scales than soft hadrons.

It seems quite non-trivial prediction...

0-5%

50

Nuclear modification factor of jet hadrons Nuclear modification factor for jets (R=0.5)

Examples of jet quenching observables at the LHС

(PYQUEN, Pb+Pb)

Medium-modified jet fragmentation function Azimuthal anisotropy of hard hadrons and jets

~106 events with jet energy ETjet > 100 GeV per «1 year» (106 sec) at the integral luminosity L=0.5 nb-1

HYDJET++ at lower energies (NICA, FAIR)

Although HYDJET++ is optimized for RHIC and LHC energies, in practice it can also be used for a wider energy range down to √s~10 A GeV. As one moves from very high to moderately high energies, the contribution of the hard part of the event becomes smaller, while the soft part turns into a multi-parameter fit to the data. For NICA and FAIR energies, input parameters of HYDJET++ soft component are tuned using SPS data.

Conclusion

Such nuclear collective effects as medium-induced partonic energy loss (jet quenching) and elliptic and radial flow carry important information about formation conditions and properties of dense QCD matter created in ultra-relativistic heavy ion collisions. RHIC data support the pattern of perfect quark-gluon fluid formation in central heavy ion collisions, which is almost “black” medium for hard partons. Will a hot medium produced in heavy ion collisions at the LHC have similar properties or completely different?

Among other heavy ion event generators (HIJING, FRITIOF, LUCIAE, UrQMD, QGSM, AMPT, THERMINATOR, ZPC...), HYDJET/HYDJET++ are concentrated on detailed simulation of jet quenching, and also reproducing main features of nuclear collective dynamics by fast (but realistic) way. The final hadron state in HYDJET/HYDJET++ represents the superposition of two independent components: hard multi-parton and soft hydro-type. The hard components of HYDJET & HYDJET++ are identical. The soft component of HYDJET++ contains the important additional features (resonance decays, separate treatment of thermal and chemical freeze-out hypersurfaces).

HYDJET++ is capable of reproducing the bulk properties of heavy ion collisions at RHIC (hadron spectra and ratios, radial and elliptic flow, femtoscopic correlations), as well as high-p

T spectra. It looks the promising

simulation tool for LHC (also at lower energies NICA & FAIR).