BORMIO 2009

Marcus Bleicher, Wrozlaw 2013Hybrid Modeling of Heavy Ion CollisionsMarcus BleicherFrankfurt Institute for Advanced StudiesInstitut fr Theoretische PhysikGoethe Universitt FrankfurtGermany

1How I learned that there is a right and wrong way to do thermodynamics ;-)

Marcus Bleicher, Wrozlaw 2013

MB, KR, FB et al, Phys.Rev.Lett. 88 (2002) 202501Marcus Bleicher, Wrozlaw 2013Thanks to Hannah Petersen (Hybrid model) now at FIAS Jan Steinheimer (Hybrid / EoS) now at LBL Marlene Nahrgang (Chiral Hydro) now at Duke Bjoern Baeuchle (Photons) Jochen Gerhard (GPU code) Yurii Karpenko (development of viscous hydro w/Nantes group) Pasi Huovinen (Hydro freeze-out) Hendrik van Hees (Heavy quark Langevin)3OutlineIntroduction/ModelBulk: PhotonsHard probes: CharmPotential improvementsSummary

Marcus Bleicher, Wrozlaw 2013Its not a uniform system...

Marcus Bleicher, Wrozlaw 2013Marcus Bleicher, Wrozlaw 2013The need for dynamic simulations

Initial StatePre-quilibriumQGP and hydro-dynamic expansionHadronisationHadronic phase and freeze-outLattice gauge- theorie (lQCD): ab initio calculation of QCD quantities usually in thermodynamic limitExperiments: Observes the final state and penetrating probes Relies on theoretical predictions for the interpretation of the dataTransport models & phenomenology: Provides explicit time and space dependence Direct view into the hot and dense matter Connects between fundamental calculations and observationMarcus Bleicher, Wrozlaw 2013Present Hybrid ApproachesIntegrated (open source) UrQMD 3.3H. Petersen, J. Steinheimer, M. Bleicher, Phys. Rev. C 78:044901, 2008MUSIC@RHIC and LHCB. Schenke, S. Jeon, C. Gale, ... (2008)Hadronic dissipative effects on elliptic flow in ultrarelativistic heavy-ion collisions.T. Hirano, U. Heinz, D. Kharzeev, R. Lacey, Y. Nara, Phys.Lett.B636:299-304,20063-D hydro + cascade model at RHIC.C. Nonaka, S.A. Bass, Nucl.Phys.A774:873-876,2006Results On Transverse Mass Spectra Obtained With NexspherioF. Grassi, T. Kodama, Y. Hama, J.Phys.G31:S1041-S1044,2005EPOS+Hydro+UrQMD at LHCK. Werner, M. Bleicher, T. Pierog, Phys. Rev. C (2010)Started with S. Bass, A. Dumitru, M. Bleicher, Phys.Rev.C60:021902,1999

Marcus Bleicher, Wrozlaw 2013Hybrid ApproachEssential to draw conclusions from final state particle distributions about initially created medium

(Petersen et al., PRC 78:044901, 2008, arXiv: 0806.1695) 1x 10-23 s 10 x 10-23 s 30 x 10-23 s

Initial nucleiQuark Gluon Plasma/HadronizationDetectorHadronicNon-equilibrium initial stateRelativistic hydrodynamicsBoltzmannMarcus Bleicher, Wrozlaw 2013Initial StateContracted nuclei have passed through each other (at least 0.5 fm)

Energy is depositedBaryon currents have separated Energy-, momentum- and baryon number densities are mapped onto the hydro gridEvent-by-event fluctuations are taken into accountSpectators are propagated separately in the cascade

(J.Steinheimer et al., PRC 77,034901,2008)(nucl-th/0607018, nucl-th/0511021)

Elab=40 AGeV b=0 fm

Marcus Bleicher, Wrozlaw 2013

From H. PetersenConstraining GranularityMarcus Bleicher, Wrozlaw 2013

From H. PetersenMarcus Bleicher, Wrozlaw 2013Equations of StateIdeal relativistic one fluid dynamics: andHG: Hadron gas including the same degrees of freedom as in UrQMD (all hadrons with masses up to 2.2 GeV)CH: Chiral EoS from quark-meson model with first order transition and critical endpointBM: Bag Model EoS with a strong first order phase transition between QGP and hadronic phase

D. Rischke et al., NPA 595, 346, 1995,D. Zschiesche et al., PLB 547, 7, 2002Papazoglou et al., PRC 59, 411, 1999J. Steinheimer, et al., J. Phys. G38 (2011) 035001

Phase diagram for the chiral EoSQGP fraction lambdaChiral PTDeconfinement PTCEPParameters fixed to lQCD at mu=0

Full line: DeconfinementDashed line: Chiral PTMarcus Bleicher, Wrozlaw 2013J. Steinheimer, S. Schramm, H. Stoecker, J. Phys. G38 (2011) 035001

Hadronization and Cooper-FryeExperiments observe finite number of hadrons in detectorsHadronization controlled by the equation of stateSampling of particles according to Cooper-Frye should:-Respect conservation laws, maybe even locally?-Introduces fluctuations on its own

Sophisticated 3D hypersurface finder to resolve interesting structures in event-by-event simulations

Petersen, Huovinen, arXiv:1206.3371

Marcus Bleicher, Wrozlaw 201314Marcus Bleicher, Wrozlaw 2013Final State Interactions (after Hydro)

Hybrid models work up to LHC energiesPbPb, 2.76 TeVExcellent description of centrality dependence,Transverse momenta,Elliptic flow.Marcus Bleicher, Wrozlaw 2013

H. Petersen, Phys.Rev. C84 (2011) 034912 chiral vs HG-EoSMarcus Bleicher, Wrozlaw 2013Photon rates: hadronic and partonicHadronic rate parametrization:

QGP rate:

Insert all rates into the hybrid model and compare to data.S. Turbide, R. Rapp, C. Gale, Phys. Rev. C69 (2004) 014903

P. Arnold, G. Moore, L. Yaffe, JHEP 0112 (2001)009Marcus Bleicher, Wrozlaw 2013Comparison to data

Bjoern Bauechle, MB, PRC (2010)

Hybrid, QGP: ChannelsComparisonsHeavy quarks at LHCEmploy Rapp, van Hees-Langevin for heavy quarks in the dynamical background good description of dataMarcus Bleicher, Wrozlaw 2013T. Lang, H. van Hees, M. Bleicher, arxiv: 1208.1643

Heavy quarks at RHICEmploy Rapp, van Hees-Langevin for heavy quarks in the dynamical background good description of dataMarcus Bleicher, Wrozlaw 2013T. Lang, H. van Hees, M. Bleicher, arxiv: 1208.1643

improvementsMarcus Bleicher, Wrozlaw 20133+1d Simulation is working100 Timesteps in FORTRAN ~60 min.100 Timesteps in C++ Version ~15 min.

J. Gerhard, M. Bleicher, V. Lindenstruth, arXiv:1206.0919, CPC2012 Marcus Bleicher, Wrozlaw 2013100 Timesteps in OpenCL Version ~30 sec.

Factor 160 speed-up!(new cards: factor 400 !)Speeding things up: GPGPUsAim: Explore signals for QCD first order phase transition and critical end pointModel: Ideal quark fluid coupled to Polyakov-quark-meson model

Propagate chiral fields and Polyakov loop explicitly via Langevin equations of motionEnergy-momentum exchange between fields and fluid described by source termsM.Nahrgang, S.Leupold, C.Herold, M.Bleicher, PRC 84 (2011); M.Nahrgang, S.Leupold, M.Bleicher, PLB 711 (2012); M.Nahrgang, C.Herold, S.Leupold, M.Bleicher, I.Mishustin arXiv:1105.1962Nonequilibrium Chiral Fluid Dynamics (NFD, PNFD)

Solve with 3+1 dim. hydro, using SHASTA and staggered leap frog for the fieldsMarcus Bleicher, Wrozlaw 2013(see also talk by H. van Hees and similar approach be C. Wesp)23Fluctuations and quark densitiesC. Herold, M. Nahrgang, M. Bleicher, I. Mishustin

Angular distribution, 12 fm/c6 fm/c12 fm/cCrossoverCP1st o. PT

Strong fluctuations,inhomogeneous quark densitiesMarcus Bleicher, Wrozlaw 2013

24SummaryHybrid models provide an excellent description of many data up to LHC- Bulk (Pions, Kaons, Protons), p_T, dN/dy- Hard probes (Charm, Bottom)- Photons, DileptonsOpen questions remain: local coupling of currents, Cooper-Frye vs collision rates...Latest improvements: Classical field dynamics

Marcus Bleicher, Wrozlaw 2013