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in collaboration with: I.Bouras, A. El, O. Fochler, F. Reining, J. Uphoff, C. Wesp, Zhe Xu

collective and hard phenomena @RHIC&LHC within an unified transport description. C. Greiner, Obergurgl, february 2011. in collaboration with: I.Bouras, A. El, O. Fochler, F. Reining, J. Uphoff, C. Wesp, Zhe Xu.

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in collaboration with: I.Bouras, A. El, O. Fochler, F. Reining, J. Uphoff, C. Wesp, Zhe Xu

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  1. collective and hard phenomena @RHIC&LHCwithin an unified transport description C. Greiner, Obergurgl, february 2011 in collaboration with: I.Bouras, A. El, O. Fochler, F. Reining, J. Uphoff, C. Wesp, Zhe Xu • early thermalization, viscosity and elliptic flow • dissipative shock waves and Mach Cones • jet quenching … same phenomena? • charming probes

  2. Schematic picture of HIC: by S.Bass time Hot Plasma: Quark-Gluonic Medium Freeze-Out & Hadronisation: Hadronic medium Decoupling: Observation in a detector

  3. Initial production of partons minijets color glass condensate string matter

  4. BAMPS: BoltzmannApproachofMultiPartonScatterings A transport algorithm solving the Boltzmann-Equations for on-shell partons with pQCD interactions new development ggg gg, radiative „corrections“ (Z)MPC, VNI/BMS, AMPT Elastic scatterings are ineffective in thermalization ! Inelastic interactions are needed ! Xiong, Shuryak, PRC 49, 2203 (1994) Dumitru, Gyulassy, PLB 494, 215 (2000) Serreau, Schiff, JHEP 0111, 039 (2001) Baier, Mueller, Schiff, Son, PLB 502, 51 (2001) BAMPS: Z. Xu and C. Greiner,PRC 71, 064901 (2005); Z. Xu and C. Greiner, PRC 76, 024911 (2007)

  5. screened partonic interactions in leading order pQCD elastic part radiative part J.F.Gunion, G.F.Bertsch, PRD 25, 746(1982) T.S.Biro at el., PRC 48, 1275 (1993) S.M.Wong, NPA 607, 442 (1996) screening mass: LPMsuppression: the formation time Lg: mean free path suppressed!

  6. P.Danielewicz, G.F.Bertsch, Nucl. Phys. A 533, 712(1991) A.Lang et al., J. Comp. Phys. 106, 391(1993) Stochastic algorithm cell configuration in space D3x for particles in D3x with momentum p1,p2,p3 ... collision probability:

  7. Heavy-ion collision at LHC BAMPS simulation of QGP phase at LHC at sNN = 2.76 TeV Visualization framework courtesy MADAI collaboration, funded by the NSF under grant# NSF-PHY-09-41373

  8. pT spectra at collision center: xT<1.5 fm, Dz < 0.4 t fm of a central Au+Au at s1/2=200 GeV Initial conditions: minijets pT>1.4 GeV; coupling as=0.3 simulation pQCD 2-2 + 2-3 + 3-2 simulation pQCD, only 2-2 3-2 + 2-3: thermalization! Hydrodynamic behavior! 2-2: NOthermalization

  9. time scale of thermalization Theoretical Result ! t = time scale of kinetic equilibration.

  10. distribution of collision angles at RHIC energies gg gg: small-angle scatterings gg ggg: large-angle bremsstrahlung

  11. Transport Rates • Transport rate is the correct quantity describing kinetic • equilibration. • Transport collision rates have an indirect relationship • to the collision-angle distribution. Z. Xu and CG, PRC 76, 024911 (2007)

  12. Transport Rates Large Effect of 2-3 !

  13. Z. Xu and CG, Phys.Rev.Lett.100:172301,2008. Shear Viscosity h Navier-Stokes approximation relation: h <-> Rtr AdS/CFT RHIC

  14. numerical extraction of viscosity- I F. Reining Starting from a classical ansatz With the Navier-stokes approximaion velocity profile finite size error

  15. numerical extraction of viscosity- II C. Wesp Green-Kubo relation: equilibrium fluctuations:

  16. numerical extraction of viscosity- II C. Wesp some examples

  17. numerical extraction of viscosity- II C. Wesp perturbative small viscosity …

  18. z y x Motion Is Hydrodynamic • When does thermalization occur? • Strong evidence that final state bulk behavior reflects the initial state geometry • Because the initial azimuthal asymmetrypersists in the final statedn/df ~ 1 + 2v2(pT) cos (2 f) + ... 2v2

  19. Elliptic Flow and Shear Viscosity in 2-3 at RHIC 2-3Parton cascade BAMPS Z. Xu, CG, H. Stöcker, PRL 101:082302,2008 viscous hydro. Romatschke, PRL 99, 172301,2007 h/s at RHIC: 0.08-0.2

  20. Rapidity Dependence of v2: Importance of 2-3! BAMPS evolution of transverse energy

  21. Mach Cones in Ideal Hydrodynamics B. Betz, M. Gyulassy, D. Rischke, H. Stöcker, G. Torrieri Box Simulation • QCD “sonic boom”

  22. Mach Cones in BAMPS Setup jet Jet has constant mean free path and only momentum in z-direction! Medium Box scenario, no expansion of the medium, massless Boltzmann gas interactions: 2  2 with isotropic distribution of the collision angle

  23. Mach Cones in BAMPS: Different Viscosities • The results agree qualitatively with hydrodynamic and transport calculations → B. Betz, PRC 79:034902, 2009 • Strong collective behaviour is observed • A diffusion wake is also visible, momentum flows in direction of the jet

  24. Mach Cones in BAMPS: Different Viscosities

  25. Mach Cones in BAMPS: Different Viscosities

  26. Mach Cones in BAMPS: Different Viscosities • The shock front (Mach front) gets broader and vanish with more dissipation • The viscosity smears the profile out, but does it affect the Mach angle?

  27. Stoped Jet in BAMPS:

  28. Stoped Jet in BAMPS:

  29. Stoped Jet in BAMPS:

  30. Stoped Jet in BAMPS:

  31. Hard probes of the medium • nuclear modification factor relative to pp (binary collision scaling) • experiments show approx. factor 5 of suppression in hadron yields high energy particles are promising probes of the medium created in AA-collisions QM 2008, T. Awes

  32. transport model: incoherent treatment ofggggg processes • parent gluon must not scatter during formation time of emitted gluon • discard all possible interference effects (Bethe-Heitler regime) p1 p2 kt kt lab frame CM frame t = 1 / kt • total boost LPM-effect O. Fochler

  33. Energy Loss in gg  ggg Processes Cross sections ( T = 400 MeV) Energy loss in single gg  ggg • Reasonable partonic cross sections over the whole energy range. • Definition of the energy loss DE matters • DE = Ein – max( Eiout ) • DE = w

  34. Gluon Radiation and Energy Loss Radiaton spectrum (E = 50 GeV) DE distribution (E = 400 GeV) • Heavy tail in DE distribution leads to large mean <DE>

  35. Some BAMPS Events (CM frame) DE = 0.67 GeV DE = 206.43 GeV DE = 26.01 GeV DE = 117.01 GeV

  36. Quenching of jets first realistic 3d results with BAMPS RAA ~ 0.052 cf. S. Wicks et al. Nucl.Phys.A784, 426 nuclear modification factor central (b=0 fm) Au-Au at 200 AGeV O. Fochler et al PRL102:202301:2009

  37. Non-Central RAA and High-pT Elliptic Flow O. Fochler, Z. Xu and C. Greiner,PRC82:024907 (2010) Gluonic RAA for b = 0 and b = 7 fm Differential v2 for b = 7 fm • inclusion of light quarks is mandatory ! • … lower color factor • jet fragmentation scheme Experimental v2 from PHENIX,arXiv:0903.4886

  38. Quenching of jets preliminary • Rates for quarks and gluons are roughly the same! • quark jet in gluon jet conversion • … needs more analysis

  39. Binary processes – RAA and v2? 10 mb, isotropic 2->2: v2 is still to low 10 mb, isotropic 2->2: jet quenching is already to strong

  40. Sensitivity on the LPM Cut-Off RAA for different X (b = 7 fm) v2 for different X (b = 7 fm)

  41. full pQCD Jet

  42. const isotropic scenario

  43. charming probes Heavy flavor in BAMPS e D _ D Initial hardpartonscatterings D D D c Energyloss Charmproduction c c D J/ψdissociation J/ψregeneration c J/ψ Pre-equil. phase c QGP D J/ψ D Jan Uphoff, Fochler, Xu, GreinerPhys. Rev. C 82 (2010) _ _ _ _ _ c c c c c

  44. Initial charm in hard parton scatterings Three approaches: LO pQCD: mini-jets NLO pQCDDistributions from R. Vogt PYTHIAMonte Carlo Event Generatorfor nucleon-nucleon collisions • both very sensitive on • parton distribution functions • factorization scale • renormalization scale • charm mass

  45. Charm production in the QGP at RHIC RHIC charm pairs BAMPS maximum of 3.4 pairs are produced J. Uphoff et al.,arXiv:1003.4200 [hep-ph]

  46. Charm production in the QGP at LHC charm pairs BAMPS LHC November run Large secondary production → Can even be comparable to initial production

  47. Elliptic flow v2 for charm at RHIC PHENIX, arXiv:1005.1627 J. Uphoff et al., arXiv:1004.4091 [hep-ph] only elastic charm processes

  48. Heavy quark elliptic flow v2 at RHIC Jan Uphoff can be fixed to by comparing dE/dx to HTL result beyond logarithmic accuracy A. Peshier, arXiv:0801.0595  [hep-ph] P.B. Gossiaux, J. Aichelin,Phys.Rev.C78 (2008)

  49. Heavy quark elliptic flow v2 at RHIC Peterson fragmentation • Impact of hadronization and decay small PHENIX, arXiv:1005.1627 only elastic processes considered

  50. Heavy quark RAA at RHIC PHENIX, arXiv:1005.1627 onlyelastic heavy quarkprocesses

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