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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 inHeavy 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 • Upsilon nuclear modification factors • Conclusions Manuel Calderón de la Barca Sánchez
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
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/ysuppression: • 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
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
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
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
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
Upsilons in STAR • Upsilons via Triggering, Calorimetry, Tracking, and matching of tracks to calorimeter towers. Manuel Calderón de la Barca Sánchez
The CMS Detector • ϒ event in CMS. Manuel Calderón de la Barca Sánchez
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
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
in p+p7 TeV in CMS • Excellent resolution at midrapidity. • Separation of 3 states. PRD 83, 112004 (2011) Manuel Calderón de la Barca Sánchez
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
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
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
in Au+Au 200 GeV, Centrality STAR Preliminary STAR Preliminary STAR Preliminary Peripheral Central Manuel Calderón de la Barca Sánchez
Bottomoniaat 2.76 TeV: 2010 data pp PbPb PRL 107 (2011) 052302 Manuel Calderón de la Barca Sánchez
Bottomonia: 2011 data pp PbPb Ratios not corrected for acceptance and efficiency Manuel Calderón de la Barca Sánchez
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
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
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
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
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
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
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
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
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