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唐泽波 中国科学技术大学近代物理系

相对论重离子碰撞中 J/ y 的产生. 唐泽波 中国科学技术大学近代物理系. Introduction J/ y production at low p T J/ y production at high p T. Discovery of J/ y. PRL33, 1404-1406 (1974). PRL33, 1406-1408 (1974). cc bound state, r~0.4 fm Mass=3.097 GeV/c 2 , Width=93.2 keV/c 2. Features of J/ y. Color octet.

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唐泽波 中国科学技术大学近代物理系

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  1. 相对论重离子碰撞中 J/y的产生 唐泽波 中国科学技术大学近代物理系 • Introduction • J/y production at low pT • J/y production at high pT Zebo Tang, 高能核物理导论

  2. Discovery of J/y PRL33, 1404-1406 (1974) PRL33, 1406-1408 (1974) Zebo Tang, 高能核物理导论

  3. cc bound state, r~0.4 fm Mass=3.097 GeV/c2, Width=93.2 keV/c2 Features of J/y Zebo Tang, 高能核物理导论

  4. Color octet Color singlet NRQCD J/y 3S1 J/y Charmonium production mechanism • Color singlet model (CSM),LO underpredicted CDF data by order of magnitude • Color octet model (COM), LO good agreement with CDF cross section disagreement with CDF polarization LO CDF measurement: PRL79,572 Know your reference! LO CSM LO COM Zebo Tang, 高能核物理导论

  5. Color octet Color singlet NRQCD Charmonium production mechanism • Color singlet model (CSM),LO underpredicted CDF data by order of magnitude • Color octet model (COM), LO good agreement with CDF cross section disagreement with CDF polarization • CSM*, NLO better agreement NNLO* applicable at pT>5-7 GeV/c • COM* improvement of polarization, NLO will come, valid at pT>3 GeV/c LO Decay feeddown (CDF): y(2s): 7%-15%, slightly increase with pT cc0,1,2: ~30%, slightly decrease with pT B: Strong pT dependence Know your reference! Zebo Tang, 高能核物理导论

  6. Low pT spectra in p+p CSM+s-channel cut works well at intermediate pT Zebo Tang, 高能核物理导论

  7. STAR Preliminary High pT spectra in p+p Significantly extend previous measurements from 5 to 14 GeV/c CEM, LO COM describe overall trend, leave little to no room for feeddown NNLO* CSM, steeper than data Zebo Tang, 高能核物理导论

  8. pT>2 GeV/c pT>5 GeV/c STAR Preliminary xT scaling n is related to the number of point-like constituents taking an active role in the interaction n=8: diquark scattering n=4: QED-like scattering  and proton at pT>2 GeV/c: n=6.6±0.1 (PLB 637, 161(2006)) J/ at high pT: n=5.6±0.2 (close to CS+CO prediction) Soft processes affect low pT J/ production Zebo Tang, 高能核物理导论

  9. Polarization Cesar Luiz da Silva, QM2009 Zebo Tang, 高能核物理导论

  10. Feeddown Susumu X. Oda, QM2008 R(ψ’) =8.6±2.5% PHENIX R(c) <42% (90%C.L.) PHENIX c→J/ +  Zebo Tang, 高能核物理导论

  11. 1) no near side correlation 2) strong near side correlation PLB 200, 380(1988) and PLB 256,112(1991) Disentangle contributions via Correlations • J/-hadron correlation can also shed light on different source contribution to J/ production • CSM vs. COM Zebo Tang, 高能核物理导论

  12. BJ/y STAR Preliminary arXiv:0904.0439 No significant near side correlation B contribution (13  5) % Little room for parton fragmentation Zebo Tang, 高能核物理导论

  13. Quark Gluon Plasma • Quark Gluon Plasma: • Deconfined and • Thermalized state of quarks and gluons Zebo Tang, 高能核物理导论

  14. Color screening of heavy quarks Ágnes Mócsy, QM2009 J/y dissociation due to color screening  Signature of the QGP formation 23 years story T. Matsui and H. Satz, PLB178, 416 (1986) Zebo Tang, 高能核物理导论

  15. ? Plasma Thermometer Ágnes Mócsy, QM2009 Quarkonium dissociation temperatures – Digal, Karsch, Satz Zebo Tang, 高能核物理导论

  16. J/y suppression in heavy-ion collisions 200 AGeV O+U collisions Central Peripheral NA38, PLB220, 471 (1989) Zebo Tang, 高能核物理导论

  17. Nuclear absorption Inelastic J/y scattering (dissociation) on primordial target and projectile nucleons  suppression of J/y Before the formation of QGP  nothing to do with QGP  Cold nuclear matter (CNM) effect C. Gerschel and J. Hufner, PLB 207, 253 (1988) A. Sibirtsev, K. Tsushima and A. W. Thomas, PRC63, 044906 Zebo Tang, 高能核物理导论

  18. Description of absorption Fully explained the J/y suppression No screening effect? C. Gerschel and J. Hufner, Z. Phys. C 56, 171 (1992) Zebo Tang, 高能核物理导论

  19. Anomalous J/y suppression NA50, NPA 610, 404 (1996) Zebo Tang, 高能核物理导论

  20. Anomalous J/y suppression NA50, Eur. Phys. J. C 39, 335 (2005) A signal of QGP formation within a “threshold-suppression” scenario J. P. Blaizot and J. Y. Ollitraut, PRL 77, 1703 (1996) Zebo Tang, 高能核物理导论

  21. Evidence of deconfinement NA 50, PLB 477,28 (2000) cc direct J/y Zebo Tang, 高能核物理导论

  22. More CNM effects Zebo Tang, 高能核物理导论

  23. Shadowing/anti-shadowing P. Amaudruz et al., NPB 441, 3 (1995) S. R. Klein and R. Vogt, PRL 91, 142301 (2003) Zebo Tang, 高能核物理导论

  24. Cronin effect Multi-scattering of the incoming gluon • Main features: • pT2 (and T) linearly increase with L (mean thickness of nuclear matter) • Phenomenological description with • the expression with an energy dependent pT2pp and a common slope: gN= 0.081±0.002 (GeV/c)2/fm Zebo Tang, 高能核物理导论

  25. Hadronic co-mover dissociation Inelastic J/y scattering (dissociation) on secondary producedhadronic comovers  Suppression of J/y  Nothing to do with QGP  Another CNM effect Sergei G. Matinyan and Berndt Muller, PRC 58, 2994 (1998) S. Gavin, M. Gyulassy and A. Jackson, PLB 207, 257 (1988) R. Vogt, M. Prakash, P. Koch and T. H. Hansson, PLB 207, 263 (1988) Zebo Tang, 高能核物理导论

  26. Parton-induce break-up in QGP The anomalous suppression depends on our understanding of CNM effects Zebo Tang, 高能核物理导论

  27. Move to higher energy Zebo Tang, 高能核物理导论

  28. J/y suppression at RHIC Scomparin (proc. QM06) : nucl-ex/0703030 Global error = 7% Global error = 12% • Similar suppression as that at SPS • More suppression at forward rapidity Zebo Tang, 高能核物理导论

  29. CNM constraints from dAu results Zebo Tang, 高能核物理导论

  30. CNM constraints from dAu results Mid-rapidity Forward/backward rapidity Zebo Tang, 高能核物理导论

  31. low x high x Forward rapidity Kharzeev, Levin, Nardi and Tuchin, 2009 Gluon saturation from non-linear gluon interactions for the high density at small x; amplified in a nucleus. • Normal CNM descriptions (blue) give similar (or even smaller) suppression at mid vs forward rapidity • but if peaking in “anti-shadowing” region were flat instead (red dashed) then one would get larger suppression for forward rapidity as has been observed in AuAu data Mike Leitch, WWND 2008 Zebo Tang, 高能核物理导论

  32. Mid-rapidity • Why the J/y suppression is similar at RHIC as that at SPS? • Regeneration • Sequential suppression Zebo Tang, 高能核物理导论

  33. Grandchamp, Rapp, Brown PRL 92, 212301 (2004) nucl-ex/0611020 Regeneration • Regeneration models give enhancement that compensates for screening • larger gluon density at RHIC expected to give stronger suppression than SPS • but larger charm production at RHIC gives larger regeneration • very sensitive to poorly known open-charm cross sections • forward rapidity lower than mid due to smaller open-charm density there • expect inherited flow from open charm • regeneration much stronger at the LHC! • Issues: • need to know what happens to C & ’ & measure J/ flow • flat forward/mid RAA seems inconsistent with increasing regeneration & screening for more central collisions Mike Leitch, WWND 2008 Zebo Tang, 高能核物理导论

  34. J/y elliptic flow Inherit open charm flow or not? Regeneration? Too early to compare to models, need more statistics Zebo Tang, 高能核物理导论

  35. Sequential suppression H. Satz, Nucl. Phys. A (783):249-260(2007) J/ suppression at low pT maybe only from excited stats (’, c) F. Karsch, D. Kharzeev and H. Satz, PLB 637, 75 (2006) 60% from direct J/: not suppressed 30% c and 10% ’: dissociated NA50, EPJ39,335 NA60, QM05 Zebo Tang, 高能核物理导论

  36. Move to high pT Zebo Tang, 高能核物理导论

  37. J/y Hot-wind dissociation H. Liu, K. Rajagopal and U.A. Wiedemann PRL 98, 182301(2007) and hep-ph/0607062 M. Chernicoff, J. A. Garcia, A. Guijosa hep-th/0607089 Possible to observe J/y suppression from directly produced J/y at high pT Zebo Tang, 高能核物理导论

  38. STAR:PRL98(2007) 192301 path length L hard parton Quark Quark Jet energy loss PHENIX:PRL98(2007)172301 c/be Strong suppress, energy loss Similar magnitude as light hadrons Zebo Tang, 高能核物理导论

  39. Nuclear modification factor RAA • Consistent with no suppression at high pT: RAA(pT>5 GeV/c) = 1.4± 0.4±0.2 • All RHIC measurements: • RAA(pT>5 GeV/c) = 1.1 ± 0.3 ± 0.2 • Indicates RAA increase from low pT to high pT • Contrast to AdS/CFT+ Hydro prediction • H. Liu, K. Rajagopal and U.A. WiedemannPRL 98, 182301(2007),T. Gunji, JPG 35, 104137(2008) • How does production mechanism (CS vs. CO) affect energy loss? • Good jobs: • transport+hydro: from initial produced instead of regenerated • Y.Liu, Zhen Qu, N. Xu and P. Zhuang, arXiv:0901.2757; N. Xu, QM2009 • two-component model: leakage and B feeddown is important • R. Rapp, X. Zhao, arXiv:0806.1239 Anti-shadowing? Zebo Tang, 高能核物理导论

  40. preliminary Upsilon Consistent with Nbin scaling Cold Nuclear Matter effects (Shadowing) are not large. RAuAu in progress Zebo Tang, 高能核物理导论

  41. Summary • J/y is a unique probe of the hot dense matter produced in heavy-ion collisions • Lots of CNM effects need to be considered • On the way to understand the screening better • As well as J/y production mechanism in hadron collisions Zebo Tang, 高能核物理导论

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