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Upsilon Production in Heavy Ions with STAR and CMS

Upsilon Production in Heavy Ions with STAR and CMS. Manuel Calderón de la Barca Sánchez . HIT Seminar Berkeley Lab September 18, 2012. Outline. Bottomonium in heavy ion collisions Upsilon measurements in: STAR CMS Upsilon cross sections in p+p

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Upsilon Production in Heavy Ions with STAR and CMS

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  1. Upsilon Production inHeavy Ions with STAR and CMS Manuel Calderón de la Barca Sánchez HIT Seminar Berkeley Lab September 18, 2012.

  2. Outline • Bottomonium in heavy ion collisions • Upsilon measurements in: • STAR • CMS • Upsilon cross sections in p+p • Upsilon nuclear modification factors • Conclusions Manuel Calderón de la Barca Sánchez

  3. Quarkoniumin the QGP • Heavy quarkonia: • Heavy quark bound state are probes of the hot QCD medium • Debye screening • Matsui & Satz, PLB 178 416 (1986) • Sequential Suppression • Digalet al., PRD 64 2001 094015 • Landau damping: Im V. • (e.g. Laine et al., JHEP 03 2007 054) ϒ T=0 0<T<TC TC<T Manuel Calderón de la Barca Sánchez

  4. High T: the interaction between the heavy quarks is modified. • Charmonium suppression: longstanding QGP signature • Original idea: High T leads to screening • Screening prevents heavy quark bound states from forming. • J/ysuppression: • Matsui and Satz, Phys. Lett. B 178 (1986) 416 • lattice calculations, indications of screening • Nucl.Phys.Proc.Suppl.129:560-562,2004 • Note: Calculations of internal energy or internal energy O. Kaczmarek, et al., Nucl.Phys.Proc.Suppl.129:560-562,2004 Manuel Calderón de la Barca Sánchez

  5. The heavy quark potential in QCD • Recent news: Heavy quark potential from (quenched) Lattice QCD • A.Rothkopf, et al. PRL 108 (2012) 162001 • Broadening due to collisions with medium (Im V) possibly more important than screening (Re V). Manuel Calderón de la Barca Sánchez

  6. Measuring the Temperature Quarkonia’s suppression pattern QGP thermometer Lattice QCD Calculations: Dissociation temperatures of quarkonia states hep-ph/0110406 • For  production at RHIC and LHC • A cleaner probe compared to J/y • co-mover absorption → negligible • recombination → negligible • d-Au: Cold Nuclear Matter Effects • Shadowing / Anti-shadowing at y~0 • Challenge: low rate, rare probe • Large acceptance detector • Efficient trigger A .Mocsy, 417th WE-Heraeus-Seminar,2008 • Expectation: • (1S) no melting • (2S) likely to melt • (3S) melts Manuel Calderón de la Barca Sánchez

  7. J/yPuzzles from SPS and RHIC • Similar J/y suppression at the SPS and RHIC! • despite 10× higher √sNN • Suppression does not increase with local energy density • RAA(forward)<RAA(mid) • Possible ingredients • cold nuclear matter effects • sequential melting • regeneration • What happens for bottomonium? Manuel Calderón de la Barca Sánchez

  8. CharmoniumvsBottomonium • J/y suppression • Hot nuclear matter effects: Suppression? Regeneration? Co-mover absorption? Energy loss? Flow? • Bottomonium Expectations • Cleaner probe of screening, deconfinement. • Regeneration? • Not a big role for bottomonium • Open bottom: sbb ~ 1.34 – 1.84 mb. • Open charm: scc~ 551 – 1400 mb. • Co-mover absorption? • Expected to be small for bottomonium • Charmoniumsabs ~ 3 – 4 mb. • Bottmoniumsabs ~ 1 mb. • Lin & Ko, PLB 503 104 (2001) Manuel Calderón de la Barca Sánchez

  9. Upsilons in STAR • Upsilons via Triggering, Calorimetry, Tracking, and matching of tracks to calorimeter towers. Manuel Calderón de la Barca Sánchez

  10. The CMS Detector • ϒ event in CMS. Manuel Calderón de la Barca Sánchez

  11.  in p+p 200 GeV in STAR 2006 2009 Phys. Rev. D 82 (2010) 12004 ∫Ldt= 7.9 ± 0.6 pb-1N(total)= 67±22(stat.) ∫Ldt = 19.7 pb-1N(total)= 145±26(stat.) STAR Preliminary Manuel Calderón de la Barca Sánchez

  12.  Comparison to NLO pQCD • Comparison to NLO • STAR √s=200 GeVp+p ++→e+e- cross section consistent with pQCDColor Evaporation Model (CEM) CEM: R. Vogt, Phys. Rep. 462125, 2008CSM: J.P. Lansberg and S. Brodsky, PRD 81, 051502, 2010 Manuel Calderón de la Barca Sánchez

  13.  in p+p7 TeV in CMS • Excellent resolution at midrapidity. • Separation of 3 states. PRD 83, 112004 (2011) Manuel Calderón de la Barca Sánchez

  14.  vs√s, World Data STAR Preliminary STAR √s=200 GeVand CMS √s=7 TeVp+p ++→e+e- cross section consistent with pQCDand world data trend Manuel Calderón de la Barca Sánchez

  15.  in d+Au 200 GeV STAR Preliminary Signal has ~8σ significance pT reaches ~ 5 GeV/c ∫Ldt= 32.6 nb-1N+DY+bb(total)= 172 ± 20(stat.) Final results on RdAu coming soon. LHC pPb run in January/February. Manuel Calderón de la Barca Sánchez

  16.  in Au+Au 200 GeV Raw yield of e+e- with |y|<0.5 = 197 ± 36 ∫Ldt ≈ 1400 µb-1 Manuel Calderón de la Barca Sánchez

  17.  in Au+Au 200 GeV, Centrality STAR Preliminary STAR Preliminary STAR Preliminary Peripheral Central Manuel Calderón de la Barca Sánchez

  18. Bottomoniaat 2.76 TeV: 2010 data pp PbPb PRL 107 (2011) 052302 Manuel Calderón de la Barca Sánchez

  19. Bottomonia: 2011 data pp PbPb Ratios not corrected for acceptance and efficiency Manuel Calderón de la Barca Sánchez

  20.  in Au+Au 200 GeV, RAA Models from M. Strickland and D. Bazow, arXiv:1112.2761v4 • Indications of Suppression of Upsilon(1S+2S+3S) getting stronger with centrality. • Reduced pp statistical uncertainties, increased statistics from 2009 data vs 2006 data. Manuel Calderón de la Barca Sánchez

  21. ϒ(2S)/ϒ(1S) Double Ratio, CMS • Separated ϒ(2S) and ϒ(3S) • Measured ϒ(2S) double ratio vs. centrality • no strong centrality dependence Manuel Calderón de la Barca Sánchez

  22. ϒ(1S) Nuclear Modification Factor: RAA • CMS PbPb at 2.76 TeV • In 2010: 7.28 µb−1 • ϒ(1S) RAA, 3 centrality bins • JHEP 1205 (2012) 063 • In 2011: 150 µb−1 • ϒ(1S) RAA, 7 centrality bins • First results on ϒ(2S) RAA • Clear suppression of ϒ(2S) • ϒ(1S) suppression • Consistent with excited state suppression only • ~50% feed down CMS Preliminary, arXiv:1208.2826 Manuel Calderón de la Barca Sánchez

  23. Comparison: RHIC and LHC • STAR measured RAA of ϒ(1S+2S+3S) combined • arXiv:1109.3891 • min. bias value: • CMS: separate RAA forϒ(1S) and ϒ(2S) • can calculate min. bias RAA of ϒ(1S+2S+3S): CMS Preliminary, arXiv:1208.2826 Manuel Calderón de la Barca Sánchez

  24. ϒ RAA Comparison to models I • Incorporating lattice-based potentials, including real and imaginary parts • A: Free energy • Disfavored, not shown. • B: Internal energy • Consistent with data vs. Npart • Includes sequential melting and feed-down contributions • ~50% feed-down from cb. • Dynamical expansion, variations in initial conditions (T0, η/S) • Data indicate: • 428 < T0 < 442 MeV at RHIC • 552 < T0 < 580 MeVat LHC • for 3 > 4pη/S > 1 • M. Strickland, PRL 107, 132301 (2011). Manuel Calderón de la Barca Sánchez

  25. ϒ RAAComparison to models II • Weak vs. Strong Binding • Narrower spectral functions for “Strong” case • Ratios of correlators compared to Lattice: favor “Strong” binding case • Kinetic Theory Model • Rate Equation: dissociation + regeneration • Fireball model: T evolution. T ~ 300 MeV Weak Binding Strong Binding Manuel Calderón de la Barca Sánchez

  26. ϒ RAA Comparison to models II • Comparison to data for “Strong” binding: • Mostly consistent with data • Little regeneration: Final result ~ Primordial suppression • Large uncertainty in nuclear absorption. Need dAu, pPb. Eur. Phys. J. A (2012) 48: 72 Manuel Calderón de la Barca Sánchez

  27. ϒRAA pT and y dependence • Indications that suppression is largest at low pT. and mid rapidity. • Need more statistics for firmer conclusions. Manuel Calderón de la Barca Sánchez

  28. The bottom line... • STAR and CMS: • ϒsuppression vs. Npart. • RAAconsistent with suppression of feed down from excited states only (~50%) • CMS: First measurement ofϒ(2S) suppression • RAA(ϒ(3S)) < 0.09 (95% C.L.) • ϒ(1S) RAA consistent with suppression of feed down from excited states only (~50%) • Needmore pp statistics to pin down lower-pT double ratio • Pinning down the medium properties. • Cold nuclear matter: • coming soon! Manuel Calderón de la Barca Sánchez

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