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Kai Zhou (Tsinghua University,Beijing)

Cold and Hot Nuclear Matter Effects on Quarknoium production at LHC. Kai Zhou (Tsinghua University,Beijing). In collaboration with: Baoyi Chen (Tsinghua University) Yunpeng Liu (Texas A&M University, USA) Zhe Xu(Tsinghua University) Nu Xu (CCNU) Pengfei Zhuang (Tsinghua University)

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Kai Zhou (Tsinghua University,Beijing)

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  1. Cold and Hot Nuclear Matter Effects on Quarknoium production at LHC Kai Zhou (Tsinghua University,Beijing) In collaboration with: Baoyi Chen (Tsinghua University) Yunpeng Liu (Texas A&M University, USA) Zhe Xu(Tsinghua University) Nu Xu (CCNU) Pengfei Zhuang (Tsinghua University) 成都2013 1

  2. Motivation • Cold & Hot Nuclear MatterEffects • Numerical results • Summary 2

  3. Early Universe (LHC, RHIC) Quark-Gluon Plasma Critical Point ? Tc （Temperature） Color Superconduct Hadron Gas QCD Phase Diagram Nucleon Gas Nuclear Matter r0 Neutron Star • Motivation Vacuum Hotter(Denser) ( Confinement ) ( Deconfinement ) QCD predicts that partons may be rel-eased from hadrons in extream conditi-ons -----New form of matter：QGP 3

  4. Motivation QGP Quark-Gluon Plasma （QGP） ? QGP signal!! Relativistic Heavy Ion Collisions 9/16/2014 4

  5. 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 suppression ●quarkonia can survive above Tc,a sensitive signature of QGP formation ●heavy quarks are produced via hard processes,rather solid theoretical ground = 1 No medium effect < 1 Suppression > 1 Enhancement 5

  6. 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 ●With increasing collision energy, hot medium effects increase or not ? 6

  7. Cold & Hot Nuclear MatterEffects Transport (Hot & Cold) + HydrodynamicApproach Hydrodynamic Evolution for the medium hot nuclear matter effects 1)dissociation 2)regeneration Transport Equation for Jpsi cold nuclear matter effects 1)absorption 2)Cronin effect 3)shadowing effect 7

  8. 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 8

  9. 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 ! Assumed charm quarks kinetically thermalized: 9

  10. Cold & Hot Nuclear MatterEffects Transport : Cold Nuclear Matter Effects ●initial conditionfor transport Eq. including Cold Effects Superposition from pp collisions (Glauber model) along with modification from CNM: Nuclear absorption Absorption Cronin effetc Cronin Cold Effects Shadowing nPDF vs. PDF 10

  11. Cold & Hot Nuclear MatterEffects Transport : Cold Nuclear Matter Effects ●initial conditionfor transport Eq. including Cold Effects Superposition from pp collisions (Glauber model) along with modification from CNM: Absorption (so at LHC can safly be neglected) Cronin pT broadening (use Gaussian smearing) @ LHC Pb-Pb 2.76TeV Init.J.Mod.Phys.E.12,211(2003) Phys.Rev. C 73, 014904(2006) 11

  12. Cold & Hot Nuclear MatterEffects Transport : Cold Nuclear Matter Effects ●initial conditionfor transport Eq. including Cold Effects Superposition from pp collisions (Glauber model) along with modification from CNM: Shadowing (for Jpsi & charm) (2 1) Colour Evaporation Model pp AA R.Vogt et al. PRL91 (2003) 142301. PRC71(2005) 054902 12

  13. 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 ● Initialization: Glauber model & constrained by Charged Multiplicitiesand from well tested HydroCode (Hirano) 13

  14. Numerical Results LHC Pb-Pb 2.76TeV : 2.5<|y|<4.0 Inclusive Jpsi the band due to the uncertainty of charm cross section 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 data from Nucl.Phys.A00,1(2012) 14

  15. Numerical Results LHC Pb-Pb 2.76TeV : 2.5<y<4 low pt part : regeneration important Raa(Np) for different pt bins: data from arXiv:1211.1623[nucl-ex] 15

  16. Numerical Results LHC Pb-Pb 2.76TeV : 2.5<|y|<4.0 Inclusive Jpsi data : ALICE 0-90% low pt region is dominat- ed by regeneration Suppression increases with increasing pt, a valley struc- ture uncertainties arised from charm cross section Regeneration signature 16

  17. Numerical Results Ridge profile for the pt structure of v2 is due to the two component mechanism: hard component (small v2)initial part soft component (large v2)regeneration Inclusive Jpsis' v2 sensitive to the strength of B quark's quench or thermalization degree. 17

  18. Numerical Results Hot Medium Effect Stronger! 1, compared to total yield, more sensitive to the ----the hot medium effects. it can indicate the production mechanism at play.. 18

  19. Numerical Results 2, sensitive to the degree of heavy quark thermalization. 3, not sesitive to the cold nuclear matter effect------ Shadowing effect. 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 model prediction. • While the total yield can hardly tell us more about the Jpsi production, theTransverse Momentum Dependense give more information. We introduce which can be used to sensitively probe the QGP formation at LHC. 20

  21. Thank You! 21

  22. Instead of the constant RAA(Bhadron)=0.4, using a realistic B quark quench factor from data&model: 22

  23. Input spectrum for Jpsi and B meson decay fraction in p-p collisions at LHC: 23 23

  24. 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: 24 24

  25. Numerical Results LHC Pb-Pb 2.76TeV : 0 <|y|<0.9 Inclusive Jpsi the band due to the uncertainty of charm cross section B-decay contribute~10% totaly Reg. vs Init.@,most central co- llisions is larger than70% :30% thermal charm production?? FONLL data from Nucl.Phys.A00,1(2012) 25

  26. Numerical Results LHC Pb-Pb 2.76TeV : high pt part : no regeneration contribute Raa(Np) for different pt bins: data from arXiv:1211.1623[nucl-ex] applied 26

  27. Numerical Results LHC Pb-Pb 2.76TeV : 2.5<|y|<4.0 Inclusive Jpsi data : ALICE 40-90% low pt region is dominat- ed by regeneration Suppression increases with increasing pt, a valley struc- ture uncertainties arised from charm cross section Regeneration signature 27

  28. Numerical Results LHC Pb-Pb 2.76TeV : |y|<2.4 Prompt Jpsi data : CMS 0-100% low pt region is dominat- ed by regeneration Suppression increases with increasing pt, even can exceed 1 uncertainties arised from charm cross section Regeneration signature 28

  29. Numerical Results LHC Pb-Pb 2.76TeV : high pt part : no regeneration contribute Raa(Np) for different pt bins: data from arXiv:1211.1623[nucl-ex] put into 29

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