1. 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)

2. 2 Ø Motivation Ø Cold & Hot Nuclear Matter Effects Ø Numerical results at RHIC and LHC Ø Summary

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

4. 4 Ø 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

5. 5 Ø Cold & Hot Nuclear Matter Effects Hydrodynamic Evolution for medium Transport Equation for Jpsi cold matter effects hot matter effects Transport (Hot & Cold) + Hydrodynamic Approach

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

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

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

9. 9 Ø 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.

10. 10 Ø 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.

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

12. 12 Ø 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 than 50% : 50% almost no centrality depende- nce above Np~100 FONLL

13. 13 Ø 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 than 70% :30% FONLL

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

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

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

17. 17 Ø Numerical Results 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 LHC Pb-Pb 2.76TeV : 2.5<|y|<4.0 Inclusive Jpsi

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

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

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

21. 21 Thank You!

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

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