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Hybrid Modeling of Heavy Ion Collisions. Marcus Bleicher Frankfurt Institute for Advanced Studies Institut für Theoretische Physik Goethe Universität Frankfurt Germany. How I learned that there is a right and wrong way to do thermodynamics ;-).
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Hybrid Modeling ofHeavy Ion Collisions Marcus Bleicher Frankfurt Institute for Advanced Studies InstitutfürTheoretischePhysik Goethe Universität Frankfurt Germany Marcus Bleicher, Wrozlaw 2013
How I learnedthatthereis a rightandwrongwayto do thermodynamics ;-) MB, KR, FB et al, Phys.Rev.Lett. 88 (2002) 202501 Marcus Bleicher, Wrozlaw 2013
Thanks to • Hannah Petersen (Hybrid model) now at FIAS • Jan Steinheimer (Hybrid / EoS) now at LBL • Marlene Nahrgang (Chiral Hydro) now at Duke • BjoernBaeuchle (Photons) • Jochen Gerhard (GPU code) • YuriiKarpenko (developmentofviscoushydrow/Nantes group) • PasiHuovinen (Hydrofreeze-out) • Hendrik van Hees (Heavy quarkLangevin) Marcus Bleicher, Wrozlaw 2013
Outline • Introduction/Model • Bulk: Photons • Hard probes: Charm • Potential improvements • Summary Marcus Bleicher, Wrozlaw 2013
Its not a uniform system... Marcus Bleicher, Wrozlaw 2013
The needfordynamicsimulations QGP and hydro-dynamic expansion Hadronic phaseand freeze-out Initial State Pre-äquilibrium Hadronisation Marcus Bleicher, Wrozlaw 2013
Present Hybrid Approaches • Integrated (open source) UrQMD 3.3H. Petersen, J. Steinheimer, M. Bleicher, Phys. Rev. C 78:044901, 2008 • MUSIC@RHIC and LHCB. Schenke, S. Jeon, C. Gale, ... (2008) • Hadronicdissipative effects on ellipticflow in ultrarelativistic heavy-ioncollisions.T. Hirano, U. Heinz, D. Kharzeev, R. Lacey, Y. Nara, Phys.Lett.B636:299-304,2006 • 3-D hydro + cascademodelat RHIC.C. Nonaka, S.A. Bass, Nucl.Phys.A774:873-876,2006 • Results On Transverse Mass Spectra Obtained With NexspherioF. Grassi, T. Kodama, Y. Hama, J.Phys.G31:S1041-S1044,2005 • EPOS+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 2013
Initial nuclei Quark Gluon Plasma/Hadronization Detector Hadronic Non-equilibrium initial state Relativistic hydrodynamics Boltzmann 10 x 10-23 s 30 x 10-23 s 1x 10-23 s Hybrid Approach • Essential todrawconclusionsfrom final stateparticledistributionsaboutinitiallycreated medium (Petersen et al., PRC 78:044901, 2008, arXiv: 0806.1695) Marcus Bleicher, Wrozlaw 2013
Initial State • Contracted nuclei have passed through each other (at least 0.5 fm) • Energy is deposited • Baryon currents have separated • Energy-, momentum- and baryon number densities are mapped onto the hydro grid • Event-by-event fluctuationsaretakenintoaccount • Spectatorsarepropagatedseparately in thecascade (nucl-th/0607018, nucl-th/0511021) Elab=40 AGeV b=0 fm (J.Steinheimer et al., PRC 77,034901,2008) Marcus Bleicher, Wrozlaw 2013
From H. Petersen Marcus Bleicher, Wrozlaw 2013
ConstrainingGranularity From H. Petersen Marcus Bleicher, Wrozlaw 2013
Equations of State Idealrelativisticone fluid dynamics: and • HG: Hadron gasincludingthe same degreesoffreedomas in UrQMD (all hadronswithmassesupto 2.2 GeV) • CH: ChiralEoSfrom quark-meson modelwithfirstordertransitionandcriticalendpoint • BM: Bag Model EoSwith a strong firstorderphasetransitionbetween QGP andhadronicphase D. Rischke et al., NPA 595, 346, 1995, D. Zschiesche et al., PLB 547, 7, 2002 Papazoglou et al., PRC 59, 411, 1999 J. Steinheimer, et al., J. Phys. G38 (2011) 035001 Marcus Bleicher, Wrozlaw 2013
Phase diagramforthechiralEoS • QGP fractionlambda • Chiral PT • Deconfinement PT • CEP • Parameters fixedtolQCDatmu=0 • Fullline: Deconfinement • Dashedline: Chiral PT J. Steinheimer, S. Schramm, H. Stoecker, J. Phys. G38 (2011) 035001 Marcus Bleicher, Wrozlaw 2013
Experiments observe finite number of hadrons in detectors Hadronization controlled by the equation of state Sampling of particles according to Cooper-Frye should:-Respect conservation laws, maybe even locally?-Introduces fluctuations on its own Hadronization and Cooper-Frye Sophisticated 3D hypersurface finder to resolve interesting structures in event-by-event simulations Petersen, Huovinen, arXiv:1206.3371 Marcus Bleicher, Wrozlaw 2013
Final State Interactions (after Hydro) Marcus Bleicher, Wrozlaw 2013
Hybrid modelsworkupto LHC energies chiralvs HG-EoS • PbPb, 2.76 TeV • Excellentdescriptionofcentralitydependence, • Transverse momenta, • Ellipticflow. H. Petersen, Phys.Rev. C84 (2011) 034912 Marcus Bleicher, Wrozlaw 2013
Photon rates: hadronicandpartonic • Hadronic rate parametrization: • QGP rate: S. Turbide, R. Rapp, C. Gale, Phys. Rev. C69 (2004) 014903 P. Arnold, G. Moore, L. Yaffe, JHEP 0112 (2001)009 Insert all ratesintothe hybrid modelandcomparetodata. Marcus Bleicher, Wrozlaw 2013
Comparison to data Comparisons Hybrid, QGP: Channels BjoernBauechle, MB, PRC (2010) Marcus Bleicher, Wrozlaw 2013
Heavy quarksat LHC • Employ Rapp, van Hees-Langevinfor heavy quarks in thedynamicalbackground gooddescriptionofdata T. Lang, H. van Hees, M. Bleicher, arxiv: 1208.1643 Marcus Bleicher, Wrozlaw 2013
Heavy quarksatRHIC • Employ Rapp, van Hees-Langevinfor heavy quarks in thedynamicalbackground gooddescriptionofdata T. Lang, H. van Hees, M. Bleicher, arxiv: 1208.1643 Marcus Bleicher, Wrozlaw 2013
improvements Marcus Bleicher, Wrozlaw 2013
3+1d Simulation is working 100 Timesteps in FORTRAN ~60 min. 100 Timesteps in C++ Version ~15 min. Speeding things up: GPGPUs • 100 Timesteps in OpenCL Version ~30 sec. • Factor 160 speed-up!(new cards: factor 400 !) J. Gerhard, M. Bleicher, V. Lindenstruth, arXiv:1206.0919, CPC2012 Marcus Bleicher, Wrozlaw 2013
Nonequilibrium Chiral Fluid Dynamics (NχFD, PNχFD) Aim: Explore signals for QCD first order phase transition and critical end point Model: Ideal quark fluid coupled to Polyakov-quark-meson model Propagate chiral fields and Polyakov loop explicitly via Langevin equations of motion Energy-momentum exchange between fields and fluid described by source terms Solvewith 3+1 dim. hydro, using SHASTA andstaggeredleapfrogforthefields (see also talkby H. van Heesandsimilarapproachbe C. Wesp) M.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:1105.1962 Marcus Bleicher, Wrozlaw 2013
Fluctuations and quark densities 6 fm/c 12 fm/c Crossover Angular distribution, 12 fm/c CP 1st o. PT Strong fluctuations,inhomogeneousquarkdensities C. Herold, M. Nahrgang, M. Bleicher, I. Mishustin Marcus Bleicher, Wrozlaw 2013
Summary Hybrid modelsprovide an excellentdescriptionofmanydataupto LHC- Bulk (Pions, Kaons, Protons), p_T, dN/dy- Hard probes (Charm, Bottom)- Photons, Dileptons Open questionsremain: localcouplingofcurrents, Cooper-Frye vscollisionrates... Latestimprovements: Classicalfielddynamics Marcus Bleicher, Wrozlaw 2013