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CPOD2014, Bielefeld, Germany, Nov.17-Nov.21, /20/2014 Huichao Song Peking University Dynamic Modeling for Relativistic Heavy Ion Collisions

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QGP-the most perfect fluid in the world? BNL News, 2005 How perfect is the QGP fluid?

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What is viscosity Shear viscosity – measures the resistance to flow Bulk viscosity – measures the resistance to expansion Heat conductivity – measures the ability of heat transfer Assume: (RHIC&LHC) act against the buildup of flow anisotropy act against the buildup of radial flow

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Hydrodynamics & its Hybrid Model

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Viscous Hydrodynamics 2+1-d: OSU, INT, Stony Brook, Pudue, Calcutta (2008), Crakow, Frankfurt(2010) … … 3+1-d: Mcgill(2011), MSU(2012), Crakow(2012), Nagoya(2013)… … Song & Heinz PLB08, PRC08 Evolution equations for shear pressure tensor and bulk pressure Assume zero net baryon density & heat conductivity at RHIC and the LHC

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Viscous Hydro + Hadron Cascade Hybrid Model Initial conditions viscous hydro hadron cascade QGPHRG H. Song, S. Bass, U. Heinz, PRC2011 viscous hydro (QGP) + URQMD (HRG) viscous hydro (QGP) + URQMD (HRG) viscous hydro (QGP & HRG) ideal hydro (QGP & HRG)

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Event-by-event hydrodynamics Single shot simulations: smoothed initial conditions (before 2010) E-b-E simulations: fluctuating initial conditions (since 2010) B. Schenke et al, Phys.Rev. C85, (2012)

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Extracting QGP viscosity from elliptic flow data – VISHNU results

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MC-KLNMC-Glauber H. Song,et.al, PRL2011 VISHNU hybrid model & QGP viscosity -Initial flow, bulk viscosity, single shot vs. e-b-e calculations -Other uncertainties (much smaller) (each of them shift V 2 by a few percent, partial cancellation among them) -Main uncertainties come from initial conditions

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V 2 at RHIC and LHC Song, Bass & Heinz, PRC 2011 The average QGP viscosity is roughly the same at RHIC and LHC

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-a nice fit of spectra for pions, kaons and proton LHC: spectra for identified hadrons Song, Bass & Heinz,PRC 2014

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Spectra of Strange & Multi-strange Hadrons -a nice fit of spectra for Lambda, Xi, and Omega X.R. Zhu, H. Song et al., in preparation

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for pions, kaons & protons at LHC A very nice fit of V 2 ( P T ) for all centrality bins at LHC from VISHNU hybrid model VISHNU Song, Bass & Heinz,PRC 2014

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v 2 of Strange & Multi-strange Hadrons -Nice descriptions of Lambda, Xi and Omega V 2 at various centralities X.R. Zhu, H. Song et al., in preparation

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Initial State Fluctuations, Final State Correlations & the QGP viscosity

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MC-KLNMC-Glauber H. Song, S. Bass, U. Heinz, T. Hirano, and C. Shen, PRL2011 Uncertainties from Initial Conditions Main uncertainties come from initial conditions MC-KLN, larger HIGHER value of QGP viscosity MC-Glauber, smaller LOWER value of QGP viscosity

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MC-KLN & MC-Glauber initializations & V 3 Qiu, Shen & Heinz, PLB2012 Pure viscous hydro simulations : V 3 prefer lower value of QGP viscosity

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-fluctuations of color charges (in the framework of CGC): IP-Glasma: B. Schenke et al., arXiv: ; [nucl-th] Correlated Fluctuation: B. Muller & A. Schafer, arXiv: [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) fluctuations of nucleon positions: MC-Glauber, MC-KLN Initialization & Pre-equilibrium: Updates after Pre-equilibriums: URQMD initialization: H.Petersen & M. Bleicher, Phys. Rev. C81, ,2010 AMPT initialization: L. Pang, Q.Wang & X.Wang, arXiv: [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. … …

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

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New Observables for Higher Order Flow Harmonics -They are all sensitive to the QGP viscosity will constrain initialization models, tightening the limit on -A further study of flow data in different aspects, using e-b-e hybrid model Luzum & Ollitrault, Qiu & Heinz,12-08 C. Gale et al

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Massive Data evaluation - particle yields - spectra - elliptic flow - triangular flow & higher order flow harmonics - event by event V n distributions - higher-order event plane correlations …... … … Exp ObservablesTheoretical Inputs: - type of initial conditions - initial flow - starting time - EoS - shear viscosity - bulk viscosity - relaxation times - freeze-out/switching cond. … … … …

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spectra HBT elliptic flow Spectra R. Soltz, et al., PRC2013 Massive data evaluation (Comprehensive Heavy Ion Model Evaluation and Reporting Algorithm) Early CHIMERA Results Please also refer to the work from MSU- DUKE collaboration, arXiv:

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Massive data evaluation Bernhard & Bass, JET collaboration

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Bulk Viscosity Long, but not full lists of articles: R.Fries et al. Phys.Rev. C (2008). J.Noronha-Hostler, J.Noronha and F.Grassi, arXiv: [nucl-th] M. Habich and P. Romatschke, arXiv: [hep-ph]. J.Noronha-Hostler, et.al., Phys.Rev. C 88, (2013) K.Dusling and T.Schäfer, Phys.Rev.C 85, (2012) P. Bozek, Phys. Rev. C81, (2010) H.Song and U.WHeinz, Phys. Rev. C81, (2010) G.Torrieri et al. Phys.Rev. C78, (2008). K. Rajagopal et al. JHEP 1003, 018(2008). A. Monnai et al. Phys.Rev. C (2009) … … …

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-Bulk viscous effects are much smaller than shear ones due to the critical slowing down near phase transition (Song & Heinz PRC09) without large contamination from bulk viscosity -One can extract the QGP shear viscosity from exp data without large contamination from bulk viscosity Visc. suppression of elliptic flow shear visc. shear+ bulk visc. ideal Song & Heinz PRC09 The interplay between shear and bulk viscosity QGP HRG Min. AdS/CF T predictio n

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Ultracentral Collisions: bulk visc. & NN correlations -MC-Glauber & MC-KLN: can not simultaneously fit V 2 and V 3 Shen, Qiu and Heinz IP+Glasma + NN correlations + bulk viscosity nicely reproduces V n in ultra-central collisions G. Denicol, QM2014

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Soft Particle Yields, Chemical & thermal Freeze-out at the LHC T ch = 165MeV T ch = 150MeV v.s. J. Stachel,SQM 2013

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dN/dy for identified hadrons (RHIC & LHC) -VISHNU nicely describes the multiplicity for pions, kaons & protons RHIC : 200 A GeV Au+AuLHC : 2.76 A TeV Pb+Pb VISHNU : T sw = 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 Song, Bass & Heinz,PRC 2014

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dN/dy for identified hadrons (LHC) -VISHNU nicely describes the multiplicity for various hadrons at the LHC X.R. Zhu, H. Song et al., in preparation

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dN/dy for identified hadrons (LHC) X.R. Zhu, H. Song et al., in preparation VISHNU most central collisions

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Statistical Model vs. VISHNU VISHNU : T sw = 165MeVStatistical Model : T ch ~ 150 MeV VISHNUStatistical Model - Statistical Model: T ch is extracted from final hadron yields; averaged chemical freeze-out temperature for final stable hadrons - VISHNU: T sw corresponds QGP chemical freeze-out; different hadrons may have different chemical freeze-out temperature.

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Chemical freeze-out for various hadrons in UrQMD X.R. Zhu, H. Song et al., in preparation

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Thermal freeze-out for various hadrons in UrQMD X.R. Zhu, H. Song et al., in preparation -earlier freeze-out for Xi and Omega!

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phi-meson

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Elliptic flow for phi at the LHC T. Hirano 3+1-d ideal hydro+JAM 200A GeV Au+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, PRC 2014

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Elliptic flow for phi at the LHC Song, Bass & Heinz, PRC 2014 ALICE 2014

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Elliptic flow for phi at the LHC Song, Bass & Heinz, PRC 2014 ALICE 2014 STAR Preliminary

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phi V 2 in strong & weakly coupling limit -hydro + T dec =165 MeV weakly coupling limit -hydro + T dec =100 MeV strong coupling limit -VISHNU: small cross sections for phi Song, Bass & Heinz, PRC 2014

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phi V 2 in strong & weakly coupling limit -hydro + T dec =165 MeV weakly coupling limit -hydro + T dec =100 MeV strong coupling limit VISHNU: small cross sections for phi ALICE 2014 Song, Bass & Heinz, PRC 2014 STAR Preliminary

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Summary

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-Slightly larger averaged QGP viscosity at the LHC -Extraction from elliptic flow data using VISHNU indicates: (MC-Glauber; MC-KLN) -Recent developments on initialization models: color charge fluctuations; multiplicity fluctuations; initial flow fluctuations … … -To implement e-b-e simulations to further study other flow will help us to constrain initialization models, tightening the limit on -New flow data: triangular flow & higher order flow harmonics, higher-order event plane correlations e-b-e v n …... -massive data evaluation are needed -VISHNU could nicely describe the yields of various hadrons -B-Bbar annihilations is important to describe the proton yields at the LHC VISHNU: an indication of different chemical freeze-out temperature for various hadrons

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