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Quarkonia Measurements by the CMS Experiment in pp and PbPb Collisions

Quarkonia Measurements by the CMS Experiment in pp and PbPb Collisions . Catherine Silvestre Tello for the CMS Collaboration. Quarkonia in Heavy Ion Collisions. Good candidates to probe the QGP in HIC

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Quarkonia Measurements by the CMS Experiment in pp and PbPb Collisions

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  1. Quarkonia Measurements by the CMS Experiment in pp and PbPb Collisions Catherine Silvestre Tello for the CMS Collaboration

  2. Quarkonia in Heavy Ion Collisions • Good candidates to probe the QGP in HIC • Large masses and (dominantly) produced at the early stage of the collision via hard-scattering of gluons • Strongly bound resonances → decreasing binding energy • The start : quarkonia should melt in the QGP • T. Matsui & H. Satz PLB178, 416 (1986) • Color Screening catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  3. A Complex Production • Production mechanism not completely understood • Many effects altering production in nuclear reactions • In pA, cold nuclear matter (CNM) effects • Extensively studied at the SPS and RHIC • But different at the LHC ? • In AA, hot medium effects J-P Lansberg (Tues) The NNLO* is not a complete NNLO → possibility of (large) uncanceled logs ! If NNLO* ≈ NLO, problem with polarization catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  4. RHIC J/y Suppression Puzzles • No increase of the suppression with local density RAA (|y|<0.35) > RAA (1.2<|y|<2.2) • Similar suppression at SPS and RHIC energies RAA (RHIC, |y|<0.35) ≈ RAA (SPS) • Possible ingredients • Suppression (gluon diss.) • Sequential melting • Gluon saturation / shadowing • Regeneration • Some combination of all J/y catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  5. SOLENOID 3.8 T B-field Cathode Strip Chambers (CSC) Resistive Plate Chambers (RPC) Drift Tube (DT) Resistive Plate Chambers (RPC) Compact Muon Solenoid MUON ENDCAPS TRACKER Add castor MUON BARREL Silicon Strips Pixels catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  6. Quarkonia in CMS • Precision quarkonia physics • High statistics run pp√s=7 TeV Lint=40 pb-1 • Nuclear modification factor • PbPb √sNN=2.76 TeVLint=7.28 mb-1 • pp√s=2.76 TeVLint=225 nb-1 • Similar hard probes statistics • Good reference • Same reconstruction algorithm PbPb catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  7. pp√s=7 TeV catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  8. Di-muons from CMS pp √s=7 TeV catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  9. Inclusive J/y pp √s=7 TeV Lint=40 pb-1 |y|<0.5 J/y |yJ/y|<0.5 s=20 MeV/c2 y’ N J/y (120.5 ± 0.8)⋅103 • b-quark physics • Quarkonia physics catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  10. B → J/y pp √s=7 TeV • Reconstruct µ+µ− vertex • Simultaneous fit • Invariant mass • Pseudo-proper decay length EPJC 71:1515 (2011) Torsten Dahms (Tues. 15h) Mihee Jo (poster 458) FLASH TALK ! 1.6<|y|<2.4 catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  11. J/y Cross Section pp √s=7 TeV PROMPT NON PROMPT • Prompt J/y production not well reproduced • Models describe non-prompt J/y production better EPJC 71:1515 (2011) catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  12.  States pp √s=7 TeV • Very good dimuon mass resolution → separation of the 3  states |hm| < 2.4 s= 100 MeV/c2 |hm| < 1 s = 67 MeV/c2 1S 1S 2S 2S 3S 3S catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  13.  Cross Section pp √s=7 TeV • Pythia (LO / CSM+COM) • Reasonable agreement in shape • But not in normalization (overestimated by about a factor 2) (1S) arXiv : 1012.5545 accepted by PRD catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  14. Quarkonia in pp • Summary of the 7 TeV run • Differential charmonia and bottomonia • Constrain production mechanisms • In progress • cc, y’, quarkonium polarization • Heavy ion reference run √s=2.76 TeV pTJ/y> 6.5 GeV/c 101±12  s = 36 MeV/c2 1026 ± 35 J/y pT m > 4 GeV/c catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  15. PbPb collisions catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  16. Di-muons by CMS in PbPb Jorge Robles Thursday 15h00 Zhen Hu Monday 19h10 Torsten Dahms Tuesday 15h00 PAS CMS HIN-10-006 catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  17. Inclusive J/y PbPb √sNN=2.76 TeV Similar resolution as in pp 734 ± 54 J/y Torsten Dahms (Tues. 15h) catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  18. First Non-Prompt J/y PbPb √sNN=2.76 TeV 90 ± 13 B → J/y b-quark physics pTJ/y> 6.5 GeV/c Torsten Dahms (Tues. 15h) Mihee Jo (poster 458) FLASH TALK ! catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  19. Corrections PbPb √sNN=2.76 TeV Acceptance from MC Efficiency : centrality dependence ~17% • Efficiency from MC, checked with data :14% systematics Hyunchul Kim (poster 460, 67) Dongho Moon (poster 459, 66) catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  20. Prompt J/y RAA vs. pT PbPb √sNN=2.76 TeV Minimum bias RAA = 0.30 ± 0.02 ± 0.02 PAS CMS HIN-10-006 pTJ/y> 6.5 GeV/c catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  21. J/y RAA vs. pT : Comparison High pTJ/y’s tendency to survive at RHIC (and SPS) is not seen at the LHC CMS pTJ/y> 6.5 GeV/c STAR pTJ/y< 8 GeV/c PHENIX lower pT catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  22. Prompt J/y RAA vs. y PbPb √sNN=2.76 TeV • Less suppression at forward rapidity for high pT • Anti-shadowing ? • CMS@pT=10 up to x2~0.02 (x1~5.10-4) CMS Q2=10 GeV2 EPS09 NLO nDSg NLO catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  23. J/y RAA vs. y : Comparison CMS for pT>3 GeV/c 1.6<y<2.4 RAA= 0.39±0.06±0.03 ALICE Low pTJ/y RAA= 0.49±0.03±0.11 • CMS : opposite trend than PHENIX but different pT • Increasing RAA going towards ALICE y range CMS pTJ/y> 6.5 GeV/c PHENIX lower pTJ/y P. Pillot (Tues.) ALICE CMS M. Wysocki (Poster) Q2=10 GeV2 EPS09 NLO nDSg NLO • CMS@pT=10 up to x2~0.02 (x1~5.10-4) • ALICE@pT=0 up to x2~0.06 (x1~2.10-5) • Watch out for anti-shadowing : catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  24. Prompt J/y RAA PbPb √sNN=2.76 TeV Central 0-10% RAA= 0.20 ± 0.03 ± 0.01 Peripheral 50-100% RAA= 0.59 ± 0.12 ± 0.10 CMS pTJ/y> 6.5 GeV/c Factor 5 suppression catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  25. J/y RAA vs. Npart Comparison STAR √s=200 GeV, J/y 5 < pT< 8 GeV/c Stronger suppression seen in CMS than at STAR 40-80% Compatible with ATLAS Rcp= 0.5 ± 0.2 CMS pTJ/y> 6.5 GeV/c STAR 5<pTJ/y<8 GeV/c Phys.Lett.B697: 294-312,2011 P. Steinberg (Mon.) R. Sandstrom (Thur.) Z. Tang (Mon.) catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  26. (parenthesis from quarkonia : b-quark energy loss) catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  27. First B → J/y RAA PbPb √sNN=2.76 TeV Minimum bias RAA = 0.37 ± 0.07 ± 0.03 Central 0-20% RAA= 0.36 ± 0.08 ± 0.03 pT J/y > 6.5 GeV/c b quark energy loss ? 20-100% catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  28. High pT Suppression PbPb √sNN=2.76 TeV B→J/y at the pT of the J/y Same level of suppression as hadrons Yen-Jie Lee(Wed. 9h) catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  29. Back to quarkonia :bottomonia catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  30.  States PbPb √sNN=2.76 TeV 86 ± 12 (1S) pT m > 4 GeV/c Zhen Hu (Mon. 19h10) catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  31. (1S) RAA PbPb √sNN=2.76 TeV • Minimum bias RAA= 0.62 ± 0.11 ± 0.10 • High pT not as suppressed ? • Need more statistics catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  32. (1S) RAA PbPb √sNN=2.76 TeV • Comparison with STAR • CMS (1S) RAA(0-100) = 0.62 ± 0.11 ± 0.10 • STAR (1+2+3S) RAA(0-60) = 0.56 ± 0.11 +0.02-0.10 R. Reed (poster) catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  33. (2S+3S) Suppression PbPb √sNN=2.76 TeV • (2S+3S) production relative to (1S) in pp and PbPb • Compare pp and PbPb through a simultaneous fit pp PbPb pT m > 4 GeV/c arXiv : 1105.4894 Submitted to PRL catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  34. (2S+3S) Suppression PbPb √sNN=2.76 TeV • Pros of a double ratio • Acceptance cancels • Efficiency cancels • Potential differences • Remaining systematics 9%, from line shapes PbPb arXiv : 1105.4894 Submitted to PRL Hypothesis: no suppression ⇒ p-value 1% Significance of the suppression 2.4 s catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  35.  Suppression PbPb √sNN=2.76 TeV • Large fraction of (1S) come from excited states • Feed down ~50% from χb for pT() >8 GeV/c • 40% suppression of (1S) • Relative suppression of (2S+3S) vs. (1S) • Observation consistent with melting of the excited states only ? • What about cold nuclear matter effects ? • Smaller σabs than at lower energy and for J/y (smaller size) • Shadowing cancelling in the (2S+3S)/(1S) ratio • pA run ? CDF: PRL84 (2000) 2094 R. Vogt, hep-ph/1003.3497 catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011 Make the plots vsNpart upsilon 1S CMS and inclusive Star

  36. Quarkonia Production with CMS • Firstnon-prompt J/y in HI • b-quark energy loss • Prompt J/y significantly suppressed • (2S)+(3S) excited states suppressed • Consistent with 40% (1S) suppression  no pT cut pTJ/y>6.5 GeV/c PAS CMS HIN-10-006 arXiv : 1105.4894 Submitted to PRL Sequential melting accessible with CMS resolution catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  37. Backup catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  38. →e+e- @ RHIC • PHENIX • Au+Au collisions • High mass correlated di-electrons are suppressed • STAR • Au+Au collisions 0-60% • 93 (1,2,3S) Nucl.Phys.A855:440-443,2011 arXiv:0907.4787 catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  39. Pseudo-proper decay length catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  40. Quarkonia Acceptance catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  41. B → J/y Fraction in PbPb and pp catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  42. B → J/y Fraction pp √s=7 TeV arxiv 1104.3038 EPJC 71:1515 (2011) catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  43. Range of predictions • Less suppression • Zhao, Rapp: Due to finite J/ψ formation time, B feed down and Cronin effect • Stronger suppression • « Hot wind » model – cc pair in motion w.r.t. hot medium ⇒ decrease of screening length. _ RAA J/y vs. pT Predictions catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  44. pp Comparison • Same pp reconstruction, including low pT J/y • Agreement of the (2S+3S)/(1S) ratio • pp 2.76 TeV • pp 7 TeV catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

  45. p-value • Generate pseudo-experiments following the null-hypothesis (i.e. no suppression) • Fit pseudo-data samples with nominal fit • Count fraction of occurrences for which the ratio (taken as test statistic) is same or lower than observed: • p-value: 0.9% • 2.4σ (1-sided Gaussian test) Could background fluctuation produce a result as extreme as observed in data? • 0.31 Zhen Hu (Purdue) Quark Matter 2011, Annecy, May 23-29 2011

  46. J/y RAA Comparison PbPb √sNN=2.76 TeV • PHENIX √s=200 GeV, inclusive J/y, pTJ/y<5 GeV/c • SPS, PHENIX, LHC: similar centrality dependence • But different pT, systems and energies CMS pT J/y>6.5 GeV/c catherine.silvestre@cern.ch (LPSC) Quarkonia CMS - Quark Matter 2011

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