Cold and Hot nuclear matter effects on Charmonium production

1. Cold and Hot nuclear matter effects on Charmonium production Kai Zhou (Tsinghua University,Beijing) In collaboration with: Baoyi Chen (Tsinghua University) Yunpeng Liu (Frankfurt University) Nu Xu (CCNU) Pengfei Zhuang (Tsinghua University) 1

2. Motivation • Cold & Hot Nuclear MatterEffects • Numerical results at RHIC and LHC • Summary 2

3. Motivation Matsui and Satz: PLB178, 416(1986): J/Psi suppression as a probe of QGP in HIC color screening -----> melting of the bound states -----> yields suppressed ●quarkonia can survive above Tc,a sensitive signature of QGP formation ●heavy quarks are produced via hard processes,rather solid theoretical ground 3

4. Motivation extract information about QGP, but many effects should be taken into account: Interplay of Hot and Cold Nuclear Matter effect: --- Cold Effects : Shadowing, Nuclear Absorption, Cronin --- Hot Effects : color screening, recombination 4

5. Cold & Hot Nuclear MatterEffects Transport (Hot & Cold) + HydrodynamicApproach Hydrodynamic Evolution for medium hot matter effects Transport Equation for Jpsi cold matter effects 5

6. Cold & Hot Nuclear MatterEffects Transport : Hot Nuclear Matter Effects ●the quarkoniumdistribution function in phase space gluon dissociation cross section by OPE (Peskin,1999) Hot Effects regeneration by detailed balance ! from Potential Model 6

7. Cold & Hot Nuclear MatterEffects Transport : Cold Nuclear Matter Effects ●initial distributionfor transport Eq. including Cold Effects for Jpsi & charm Shadowing R. Vogt, Phys. Rev. C 71 (2005) 054902 Cold Effects at LHC can safly be neglected Absorption Cronin pT broadening (Gaussian smearing) @ LHC Pb-Pb 2.76TeV Init.J.Mod.Phys.E.12,211(2003) Phys.Rev. C 73, 014904(2006) 7

8. Cold & Hot Nuclear MatterEffects Hydrodynamic : Background Medium Evolution ● 2+1D hydrodynamics( ) Longitudinal Bjorken Expansion ●Equation Of State: Ideal Gas with quarks and gluons for QGP & HRG ● Initial conditions : Glauber model & constrained by Charged Multiplicities or from well tested HydroCode 8

9. Numerical Results RHIC Au-Au 0.2TeV : Ratio of 1.2<y<2.2 to |y|<0.35 rule out the approach with only cold matter effects. shadowing effect is important, and the total yield is sensitive to it. 9

10. Numerical Results RHIC Au-Au 0.2TeV : Ratio of 1.2<y<2.2 to |y|<0.35 rule out the approach with only cold matter effects. transverse momentum is not so sensitive to shadowing. 10

11. Numerical Results LHC Pb-Pb 2.76TeV : Inclusive Jpsi picked out from talk by E. Scomparin at QM2012( fot the ALICE Collaboration) 11

12. Numerical Results LHC Pb-Pb 2.76TeV : 2.5<|y|<4.0 Inclusive Jpsi the band due to considering or not considering Shadowing B-decay contribute~10% totaly Reg. vs Init.@,most central co- llisions is larger than50% : 50% almost no centrality depende- nce above Np~100 FONLL 12

13. Numerical Results LHC Pb-Pb 2.76TeV : 0 <|y|<0.9 Inclusive Jpsi the band due to considering or not considering Shadowing B-decay contribute~10% totaly Reg. vs Init.@,most central co- llisions is larger than70% :30% FONLL 13

14. prediction • Numerical Results LHC Pb-Pb 2.76TeV : Raa(Np) for different pt bins: 14

15. prediction • Numerical Results LHC Pb-Pb 2.76TeV : Raa(Np) for different pt bins: 15

16. Numerical Results LHC Pb-Pb 2.76TeV : 2.5<|y|<4.0 Inclusive Jpsi data : ALICE 0-90% low pt region is dominated by regeneration Suppression increases with increasing pt, a valley struc- ture unvertainties arised from shadowing effect picked out from talk by E. Scomparin at QM2012 16

17. Numerical Results LHC Pb-Pb 2.76TeV : 2.5<|y|<4.0 Inclusive Jpsi data : ALICE 0-90% low pt region is dominated by regeneration Suppression increases with increasing pt, a valley struc- ture uncertainties arised from shadowing effect 17

18. Numerical Results hot medium effect stronger 1,compared to total yield, not so sensitive to the cold nuclear matter effects. 2, very sensitive to the degree of heavy quark thermalization. 18

19. Numerical Results hot medium effect stronger 1,compared to total yield, not so sensitive to the cold nuclear matter effects. 2, very sensitive to the degree of heavy quark thermalization. 19

20. Summary • Both the cold and hot nuclear matter effects are included self-consistently in the transport approach and the recent data support our prediction. • While the total yield is sensitive to both the cold and hot effects,theTransverse Momentum Dependenseis mainly controlled by the hot effect. we introduce which can be used to probe the QGP formation at RHIC and LHC. 20

21. Thank You! 21

22. Input ● medium evolution ● initial production ● regeneration 22 22

23. Charmonium in pp Collisions observation: difficult to observe ψ’ ! Ψ’ and χc decay into J/ψ: Ψ’ χc J/ψ mechanisms for quarkonium production in pp:it is difficult to describe quarkonium formation due to confinement problem 1) color evaporation model: 2) color-singlet model: 3) color-octet model: 23 23