NFQCD2013, Kyoto, Japan, Nov.18-Dec.20,2013

12/04/2013

Dynamical Modeling and Soft Physics at RHIC and the LHC

Huichao Song Peking University

Selected Topics:(1) QGP viscosity at RHIC and the LHC(2) Initial State fluctuations & final state correlations(3) Elliptic flow for strange & multi-strange hadrons (4) Soft particle yields and Chemical Freeze-out at the LHC(5) Dynamical modeling near the critical point

Viscous Hydrodynamics

0)( xT gpuupeT )()(

u

TT

212

viscous hydrodynamics

Assume zero net baryon density & heat conductivity at RHIC and LHC

Song & Heinz PLB08, PRC08

2+1-d: OSU, INT, Stony Brook, Pudue, Calcutta (2008), Crakow, Frankfurt(2010)

3+1-d: Mcgill(2011), MSU(2012), Crakow(2012), Nagoya(2013)

Neglect bulk viscosity

Viscous Hydro + hadron Cascade Hybrid Model

Initial conditions viscous hydro hadron cascade

QGP HRG HRG

H. Song, S. Bass, U. Heinz, PRC2011

viscous hydro (QGP) + URQMD (HRG)

viscous hydro (QGP & HRG)

ideal hydro (QGP & HRG)

Event-by-event hydrodynamicsSingle shot simulations: smoothed initial conditions (before 2010) E-b-E simulations: fluctuating initial conditions (since 2010)

B. Schenke et al, Phys.Rev. C85 (2012) 024901

(1)Extracting QGP viscosity from elliptic flow data – VISHNU results

MC-KLN MC-GlauberH. Song, S. Bass, U. Heinz, T. Hirano, and C. Shen, PRL2011

VISHNU hybrid model & QGP viscosity (2011)

-Initial flow, bulk viscosity, single shot vs. e-b-e calculations-Other uncertainties (much smaller)

)41(5.2)/()41(1 QGPs

(each of them shift V2 by a few percent, partial cancellation among them)

-Main uncertainties come from initial conditions

V2 and QGP viscosity at the LHCSong, Bass & Heinz, PRC 2011

Please also refer to C. Gale, et al., ArXiv: 1209.5330 [nucl-th] The average QGP viscosity is slightly larger at the LHC

-a nice fit for pions, kaons and proton spectra

H. Song, S. Bass, U. Heinz, arXiv:13110157 [nucl-th]

LHC: spectra for identified hadrons

A very nice fit of V2(PT) for all centrality bins at LHC from VISHNU hybrid model

VISHNU

LHC: for identified hadrons )(2 TpVH. Song, S. Bass, U. Heinz, arXiv:13110157 [nucl-th]

(2) Initial State Fluctuations, Final State Correlations

& the QGP viscosity

MC-KLN MC-GlauberH. Song, S. Bass, U. Heinz, T. Hirano, and C. Shen, PRL2011

Uncertainties from Initial Conditions

Main uncertainties come from initial conditions

)41(5.2)/()41(1 QGPs

MC-KLN, larger HIGHER value of QGP viscosity MC-Glauber, smaller LOWER value of QGP viscosity 2

2

MC-KLN & MC-Glauber initializations & V3 Qiu, Shen & Heinz, PLB2012Pure viscous hydro simulations :

V3 prefer lower value of QGP viscosity

22 / v 22 / v

33 / v 33 / v20.0/ KLN,MC s

20.0/ KLN,MC s 08.0/ Glb,MC s

08.0/ Glb,MC s

-fluctuations of color charges (in the framework of CGC):

IP-Glasma: B. Schenke et al., arXiv:1202.6646; 1206.6805 [nucl-th] Correlated Fluctuation: B. Muller & A. Schafer, arXiv:1111.3347 [hep-ph].

-fluctuations of local gluon numbers (in the famework of MC-KLN):

Multiplicity fluctuations: A. Dumitru and Y. Nara, Phys. Rev. C 85, (2012) 034907

-fluctuations of nucleon positions: MC-Glauber, MC-KLN

Initialization & Pre-equilibrium: Updates after 2011

-Pre-equilibriums:

URQMD initialization: H.Petersen & M. Bleicher, Phys. Rev. C81, 044906,2010 AMPT initialization: L. Pang, Q.Wang & X.Wang, arXiv:1205.5019[nucl-th]

EPOS/NEXUS initialization: K. Werner et al., Phys. Rev. C83:044915,2011

Mostly, the effects of initializations /pre-equilibrium dynamics was studied with ideal hydro. Their quantitative influences on are still unknown.

… … … …

QGPs)/(

Flow at RHIC & LHC: results from IP-Glasma + MUSIC Gale, Jeon ,Schenke, Tribedy &Venugopalan PRL2013

New Observables for Higher Order Flow Harmonics

-They are all sensitive to the QGP viscosity

will constrain initialization models, tightening the limit on

QGPs)/(-A further study of flow data in different aspects, using e-b-e hybrid model

Luzum & Ollitrault, 2012-10

Qiu & Heinz,12-08

C. Gale et al.12-09

spectra

HBT

elliptic flow

Spectra

R. Soltz, et al., arXiv:1208.0897[nucl-th]

Massive data evaluating

(Comprehensive Heavy Ion Model Evaluation and Reporting Algorithm)

-- Massive data evaluating algorithm becoming available

Early CHIMERA Results

QGP viscosity at RHIC and the LHC

H. Song, NPA2013

RHIC

LHC

(1)

(2)(3)

(4)

(5)

(1) Luzum & Romatschke, PRC 2008 (2) Song, Bass, Heinz, Hirano, and Shen, PRL2011, PRC2011

(4) Qiu, Shen & Heinz, PLB 2012(5) Gale, Jeon ,Schenke, Tribedy & Venugopalan, PRL2013

(3) Song, Bass, Heinz, PRC2011

(3) Soft Particle Yields & Chemical Freeze-out Temperature at the LHC

Tch = 164MeV

Tch = 150MeV

v.s.

J. Stachel,SQM 2013

dN/dy for identified hadrons (RHIC & LHC)

-VISHNU nicely describes the multiplicity for pions, kaons & protons

RHIC : 200 A GeV Au+Au LHC : 2.76 A TeV Pb+Pb

VISHNU: Tsw= 165MeV

H. Song, S. Bass, U. Heinz, arXiv:1311.0157 [nucl-th]

dN/dy for identified hadrons (RHIC & LHC)

-VISHNU nicely describes the multiplicity for pions, kaons & protons

RHIC : 200 A GeV Au+Au LHC : 2.76 A TeV Pb+Pb

VISHNU : Tsw= 165MeV

-B-Bbar annihilations plays an important role for a nice fit of the proton data

Please also refer to F. Becattini et al., PRC2012

H. Song, S. Bass, U. Heinz, arXiv:13110157 [nucl-th]

dN/dy for identified hadrons (RHIC & LHC)

-B-Bbar annihilations plays an important role for a nice fit of the proton data

VISHNU : Tsw= 165MeV

Statistical Model : Tch~ 150 MeV (no B-Bbar annihilations!)

LHC : 2.76 A TeV Pb+Pb

A system with B-Bbar annihilations does not reach chemical freeze-out !

J. Stachel,SQM 2013

(4) Elliptic flow for Strange & multi-strange hadrons

v2 of Strange & Multi-strange HadronsSong et al., arXiv:1310.3462 [nucl-th]

-Nice descriptions of Lambda, Xi and Omega V2 at various centralities

UrQMD freeze-out time distributions

-On Average Lamba freeze-out even later than pion and protons! -earlier freeze-out for Xi and Omega!

Preliminary

pions

Omega

Lambdaproton

Xi

Song et al., in preparation

VISHNU vs Hydro with Tdec =165 & 100 MeV

-freeze-out temperature for Lambda is much below Tc! -freeze-out temperatures for Omega and xi are closer to Tc!

Preliminary

Song et al., in preparation

phi-meson

Elliptic flow for phi at the LHC

T. Hirano3+1-d ideal hydro+JAM

200A GeVAu+Au -Hadron cascade: small cross

sections for phi-mass ordering between phi and proton are independent of collision energies, centralities & theoretical details

Song, Bass & Heinz, arXiv:1311. 0157

Elliptic flow for phi at the LHC

T. Hirano3+1-d ideal hydro+JAM

200A GeVAu+Au

200A GeVAu+Au

Song, Bass & Heinz, arXiv:1311. 0157

phi V2 in strong & weakly coupling limit

-hydro + Tdec =165 MeV weakly coupling limit -hydro + Tdec =100 MeV strong coupling limit VISHNU: small cross sections for phi

Neither the strongly nor the weakly coupling limit nor the cases in between (VISHNU) could explain the mass-ordering between proton & phi shown by STAR

phi-meson puzzle !

H. Song, S. Bass, U. Heinz, arXiv:13110157 [nucl-th]

Critical Fluctuations :

22 ~)( N

~At critical point :Size effects: 3fm)-O(2

It is important to address the effects from dynamical evolutions

dynamical modeling near the critical point

(6) Beyond Hydrodynamics

5.43 ~)( N73 ~)( N

0

qqgUeff

ST fluid

)( 2

uU

uS eff

order parameter

quark & anti-quark is treated as the heat bath (fluid), which interact with the chiral field via effective mass g

Dynamical modeling near the critical point -mean field approximation

K. Peach, H. Stocker and A. Dumitru, PRC2003

),(][21)]([ 5

UqigiqL

)0(

),(][21)]([ 5

UqigiqL

propagation of initial fluctuations-mean field approximation

K. Peach, H. Stocker and A. Dumitru, PRC2003

fluidg=5.5

fluid g=3.7

0

qqgUeff

ST fluid

)( 2

uU

uS eff

)0(

First -orderCritical point

Dynamical modeling near the critical point -beyond mean field

t

eff qqgU

ST fluid

)( 2

uU

uS eff

: damping

: noise,

Jiang &Songpreliminary

M.Nahrgang, S.leupold. C. Herold, M. Bleicher , PRC 2011

Dynamical modeling near the critical point (Chiral fluid dynamics with a Polyakov loop PNJL) C. Herold, et, al. PRC 2012

First -order Critical point

-To compare with the experimental data, systematic treatment of freeze-out with external field is necessary

(1) QGP viscosity at RHIC and the LHC

(2) Initial state fluctuations & final state correlations

(3) Soft particle yields & chemical freeze-out at the LHC

(4) Elliptic flow for strange & multi-strange hadrons

-Approximately similar averaged QGP viscosity at RHIC and LHC energies - (MC-Glauber; MC-KLN))4/1(5.2)/()4/1( QGPs

-New observables to constrain QGP viscosity & initial conditions

-B-Bbar annihilation plays an important role for proton yields -Effective chemical freeze-out of the system with B-Bbar annihilation

-phi-elliptic flow needs a better understanding

(5) Dynamical modeling near the critical point -External sigma field re-organize the structure of initial & internal fluctuations -systematic treatment of the freeze-out with external field is needed in the future

Summary

Thank you