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Quarkonia with the first LHC data in ALICE

Quarkonia with the first LHC data in ALICE. Mercedes Ló pez Noriega IPNO 25/09/2009. Heavy quarks at the LHC. Heavy quarks (c and b) will be abundantly produced in heavy ion collisions. Produced in the initial parton collisions, they can be used to probe deconfinement

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Quarkonia with the first LHC data in ALICE

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  1. Quarkonia with the first LHC data in ALICE Mercedes López Noriega IPNO 25/09/2009

  2. Heavy quarks at the LHC • Heavy quarks (c and b) will be abundantly produced in heavy ion collisions. • Produced in the initial parton collisions, they can be used to probe deconfinement • Upsilon (bb) will be produced in an amount of the order of J/ at RHIC • Some effects might become important: • heavy quarks energy loss in QGP • contributions from secondary quarkonia ALICE • |η| < 0.9 and -4 <η< -2.5 • Small xBj (10-3 –10-5) Mercedes López Noriega Rencontre ions lourds – Orsay 25/09/2009

  3. Why quarkonia? • Quarkonia: bound states of heavy quarks • Charmonia (cc): J/, ’, c • Bottomonia (bb): (1S), (2S), (3S) • J/ production used as a probe of formed medium • A deconfined medium  J/ suppression due to color screening (Matsui and Satz, Phys. Lett. B 178 (1986)) • Hard gluons needed for breaking J/ not available in hadron gas (D. Kharzeev and H. Satz, Phys. Lett. B477 (2000)) • Calculations using lattice QCD: sequential suppression  suppression of states is determined by Tand their binding energy • ’, c dissolves at T ~ TC • J/ dissolves at T ~ 1.5 - 2 TC (Satz, J.Phys.G32 (2006)) Mercedes López Noriega Rencontre ions lourds – Orsay 25/09/2009

  4. J/ at the LHC SPS RHIC LHC J/ regeneration? F.Karsch et al.: PLB637 75 (2006) J/ finally melts? • The suppression has been observed at SPS and RHIC, BUT! • Similar suppression at SPS and RHIC • Stronger suppression at forward than at mid-rapidity • The results from PbPb collisions at 5.5 TeV will disentangle between the different suppression/regeneration scenarios • Measuring either an excess on J/ production or a complete melting would imply deconfinement. • An excess on the production would also indicate thermalization • But we should take into account that: • bb cross-section will be large: ~ 20% of J/y originate from B decays (B+/- J/ + X+/-) • CNM effects will not be easy to quantify at the beginning (no pA run soon) Mercedes López Noriega Rencontre ions lourds – Orsay 25/09/2009

  5. ALICE • Central |η| < 0.9, in e+e- • tracking: ITS, TPC, TRD • PID: TRD (e id.), TOF • secondary vertexing: ITS -4.0 < η< -2.5, in μ+μ- Muon Arm ITS TPC TRD TOF Mercedes López Noriega Rencontre ions lourds – Orsay 25/09/2009

  6. First pp run at the LHC Present scenario (July 09) √spp = 7 TeV Federico Antinori - Physics Forum - July 2009 Mercedes López Noriega Rencontre ions lourds – Orsay 25/09/2009

  7. What ALICE will measure assuming (just to get a feeling…): • “Pilot Run” conditions (as in previous slide) • 1 kHz TPC rate • 300 k effective sec / month (12% overall efficiency) [serious uncertainties in all three…] What do we get for each 100 nb-1? e.g.: 40 Hz single muon low pT trigger rate (based on ALICE-INT-2006-0002) • ~ 13 000 J/ψ (~150 with pT > 11 GeV/c) • ~ 250 ψ‘ • ~ 140 Υ • ~ 35 Υ‘ • ~ 20 Υ‘‘ Federico Antinori - Physics Forum - July 2009 Mercedes López Noriega Rencontre ions lourds – Orsay 25/09/2009

  8. Quarkonia analysis in pp • Baseline for the analysis in PbPb collisions • J/ and Υ production yield and cross section • J/ polarization • Upsilon family? • CGC dielectron channel Mercedes López Noriega Rencontre ions lourds – Orsay 25/09/2009

  9. Quarkonia via μ+μ- in pp pp at 14 TeV, one year of data taking (integrated luminosity = 30 pb-1) Mercedes López Noriega Rencontre ions lourds – Orsay 25/09/2009

  10. Secondary J/ψ • tot J/ψ • J/ψ from B • bkg • sum • χc: contribution ~30% • χc  J/ψ+γ • J/ψ in dielectron channel • γ in γ-convertion • feasible in pp collisions but requires a trigger strategy which is under study • B mesons: contribution ~20% • B  J/ψ+X • non-photonic electrons • “B tagging”: simultaneous fit • Invariant mass distribution • Pseudo proper decay time • In muon arm • method using 3 muon events is under study Mercedes López Noriega Rencontre ions lourds – Orsay 25/09/2009

  11. J/ψ polarization • Polarization • Angular distribution of μ+ in the quarkonium rest frame. • Upsilon polarization • 1 nominal year for integrated studies • Several years for differentials Mercedes López Noriega Rencontre ions lourds – Orsay 25/09/2009

  12. Here in Orsay... • J/ψ production yield and cross section in the dimuon channel • dN/dpT: • yield with proper background estimation • study different fitting procedures • Corrections • efficiency correction • acceptance correction • Systematic errors • uncertainty on efficiency and acceptance corrections... • Estimation J/ψ coming from B • method using 3 muon events is under study • CGC (more in next slide...) Mercedes López Noriega Rencontre ions lourds – Orsay 25/09/2009

  13. J/Ψ RCP: looking for the CGC x region probed by J/ψ production in p-p 14 TeV in the forward muon spectrometer • Event multiplicity groups: • B: small multiplicity [0-70] • M: medium multiplicity [70-95] • H: high multiplicity [95-150] Mercedes López Noriega Rencontre ions lourds – Orsay 25/09/2009

  14. PbPb collisions at the LHC Probably smaller!! Only possibility for 2009-2010 Mercedes López Noriega Rencontre ions lourds – Orsay 25/09/2009 J. Jowett, LHC Performance Workshop - Chamonix 2009

  15. Analyses with the first PbPb collisions • Quarkonia production yields and cross sections • Quarkonia production suppression: • With respect to • Beauty • pp (RAA) • As a function of • Centrality • Transverse momentum • Rapidity • J/Ψ polarization • v2 of J/ψ? • Upsilon family? • CGC? Mercedes López Noriega Rencontre ions lourds – Orsay 25/09/2009

  16. Quarkonia in PbPb collisions (nominal PbPb year) Dielectron channel Dimuon channel Mercedes López Noriega Rencontre ions lourds – Orsay 25/09/2009

  17. We have plenty of work to do Mercedes López Noriega Rencontre ions lourds – Orsay 25/09/2009

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