Steffen A. BassModeling of RHIC Collisions #1 Steffen A. Bass Duke University Relativistic Fluid Dynamics Hybrid Macro+Micro Transport flavor dependent freeze-out Hard-Probes I: Jet-Quenching Hard-Probes II: Heavy Quarks Hard Probe - Medium Interactions in 3D-Hydrodynamics in collaboration with: M. Asakawa B. Mueller C. Nonaka T. Renk J. Ruppert
Steffen A. BassModeling of RHIC Collisions #2 The Great Wall Heavy-ion collisions at RHIC have produced a state of matter which behaves similar to an ideal fluid (3+1)D Relativistic Fluid Dynamics and hybrid macro+micro models are highly successful in describing the dynamics of bulk QCD matter Jet energy-loss calculations have reached a high level of technical sophistication (BDMPS, GLV, higher twist…), yet they employ only very simple/primitive models for the evolution of the underlying deconfined medium… need to overcome The Great Wall and treat medium and hard probes consistently and at same level of sophistication!
Steffen A. BassModeling of RHIC Collisions #3 Relativistic Fluid Dynamics C. Nonaka & S.A. Bass: PRC in print, nucl-th/
Steffen A. BassModeling of RHIC Collisions #4 Relativistic Fluid Dynamics transport of macroscopic degrees of freedom based on conservation laws: μ T μν =0 μ j μ =0 for ideal fluid: T μν = (ε+p) u μ u ν - p g μν and j i μ = ρ i u μ Equation of State needed to close system of PDE’s: p=p(T,ρ i ) connection to Lattice QCD calculation of EoS initial conditions (i.e. thermalized QGP) required for calculation Hydro assumes local thermal equilibrium, vanishing mean free path This particular implementation: fully 3+1 dimensional, using (τ,x,y,η) coordinates Lagrangian Hydrodynamics coordinates move with entropy-density & baryon-number currents trace adiabatic path of each volume element
Steffen A. BassModeling of RHIC Collisions #5 3D-Hydro: Parameters EOS (entropy density) =0 0 =0.5 =1.5 max =55 GeV/fm 3, n Bmax =0.15 fm -3 0 =0.6 fm/c longitudinal profile: transverse profile: Initial Conditions: Energy Density: Baryon Number Density: Parameters: Initial Flow: v L = Bjorken’s solution); v T =0 Equation of State: Bag Model + excluded volume 1 st order phase transition (to be replaced by Lattice EoS)
Steffen A. BassModeling of RHIC Collisions #6 3D-Hydro: Results separate chemical f.o. simulated by rescaling p,K 1 st attempt to address all data w/ 1 calculation decent agreement centrality dependence of v 2 problematic b=6.3 fm Nonaka & Bass, PRC in print (nucl-th/ ) See also Hirano; Kodama et al.
Steffen A. BassModeling of RHIC Collisions #7 Hybrid Hydro+Micro Approaches C. Nonaka & S.A. Bass: PRC in print, nucl-th/
Steffen A. BassModeling of RHIC Collisions #8 Full 3-d Hydrodynamics QGP evolution Cooper-Frye formula UrQMD t fm/c hadronic rescattering Monte Carlo Hadronization TCTC T SW Bass & Dumitru, PRC61,064909(2000) Teaney et al, nucl-th/ Nonaka & Bass, PRC & nucl-th/ Hirano et al. PLB & nucl-th/ D-Hydro + UrQMD Model ideally suited for dense systems –model early QGP reaction stage well defined Equation of State parameters: –initial conditions –Equation of State Hydrodynamics + micro. transport (UrQMD) no equilibrium assumptions model break-up stage calculate freeze-out includes viscosity in hadronic phase parameters: –(total/partial) cross sections matching condition: use same set of hadronic states for EoS as in UrQMD generate hadrons in each cell using local T and μ B
Steffen A. BassModeling of RHIC Collisions #9 3D-Hydro+UrQMD: Results good description of cross section dependent features & non-equilibrium features of hadronic phase
Steffen A. BassModeling of RHIC Collisions #10 3D-Hydro+UrQMD: Reaction Dynamics Hadronic Phase: significant rescattering ±3 units in y moderate increase in v 2 rescattering of multi-strange baryons strongly suppressed rescattering narrows v 2 vs. η distribution
Steffen A. BassModeling of RHIC Collisions #11 3D-Hydro+UrQMD: Freeze-Out full 3+1 dimensional description of hadronic freeze-out; relevant for HBT
Steffen A. BassModeling of RHIC Collisions #12 Hard Probes I: Jet-Quenching T. Renk, J. Ruppert, C. Nonaka & S.A. Bass: nucl-th/ A. Majumder & S.A. Bass: in preparation
Steffen A. BassModeling of RHIC Collisions #13 Jet-Quenching in a Realistic Medium use BDMPS jet energy loss formalism (Salgado & Wiedemann: PRD68: ) define local transport coefficient along trajectory ξ: connect to characteristic gluon frenqency: medium modeled via: 1.2+1D Hydro (Eskola et al.) 2.parameterized evolution (Renk) 3.3+1D Hydro (Nonaka & Bass) ± 50% spread in values for K systematic error in tomography analysis due to different medium treatment need more detailed analysis to gain predictive power see talk by T. Renk for details
Steffen A. BassModeling of RHIC Collisions #14 Azimuthal Dependence of Energy-Loss pathlength of jet through medium varies as function of azimuthal angle distinct centrality and reaction plane dependence stronger constraints on tomographic analysis collective flow effect on q: only small modification of shape (ρ: flow rapidity; α: angle of trajectory wrt flow)
Steffen A. BassModeling of RHIC Collisions #15 Hard Probes II: Heavy-Quarks S.A. Bass, M. Asakawa & B. Mueller: in preparation
Steffen A. BassModeling of RHIC Collisions #16 Diffusion of Heavy Quarks in a Hydrodynamic Medium propagation of heavy quarks in a QGP medium resembles a diffusion process use evolution of 3D-Hydro as medium T, μ and v flow are known as function of r& τ describe propagation with a Langevin Eqn: drag coefficient κ/2T can be locally calculated from 3D hydro evolution Teaney & Moore: PRC 71, (2005) Van Hees, Greco & Rapp: PRC73, (’06) Bass, Asakawa & Mueller in preparation
Steffen A. BassModeling of RHIC Collisions #17 Summary and Outlook Heavy-Ion collisions at RHIC have produced a state of matter which behaves similar to an ideal fluid Hydro+Micro transport approaches are the best tool to describe the soft, non-perturbative physics at RHIC after QGP formation fully (3+1)D implementations are available and work very well the same hydrodynamic evolution should be utilized as medium for sophisticated jet energy-loss (currently: BDMPS and HT) and heavy quark diffusion calculations azimuthal dependence of jet energy-loss improves constraints on jet- tomography parameters consistent treatment of hard and soft physics in one framework next step: incorporate effects of hard probes on medium
Steffen A. BassModeling of RHIC Collisions #18 The End