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Observables in heavy-ion collisions at CMS

Observables in heavy-ion collisions at CMS. Haidong Liu 2009-10-21. outline. The CMS detector Review of the ‘golden’ observables Other interesting observables for me LHC schedule (latest version). CMS detectors. Silicon pixel detector Silicon microstrip tracker

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Observables in heavy-ion collisions at CMS

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  1. Observables in heavy-ion collisions at CMS Haidong Liu 2009-10-21

  2. outline • The CMS detector • Review of the ‘golden’ observables • Other interesting observables for me • LHC schedule (latest version)

  3. CMS detectors • Silicon pixel detector • Silicon microstrip tracker • Electromagnetic Calorimeter • Hadronic Calorimeter • Superconducting Solenoid • Muon detectors • Drift Tubes (barrel) • Cathode Strip Chambers (endcaps) • Resistive Plate Chambers (barrel+endcaps) • CASTOR Calorimeter (forward) • Zero Degree Calorimeter (forward) (Jet with cone size R=0.5)

  4. Low pT PID spectra for Pb+Pb @ 5.5 TeV

  5. Event plane resolution b=9fm of Pb+Pb collisions -- the expected resolution is 0.37 rad with ECAL NA49 Phys. Rev. C 68 034903 PHOBOS nucl-ex/0610037 PHOBOS Nucl. Phys. A 774 523–26 STAR AIP Conf. Proc. 870 691–4 Voloshin S A and Poskanzer A M Phys. Lett. B 474 27–32 Kolb P F, Sollfrank J and Heinz U W ,Phys. Rev. C 62 054909 Teaney D, Lauret J and Shuryak E V nucl-th/0110037 Φsimu-Φreco J. Phys. G: Nucl. Part. Phys. 34 (2007) 2307-2455

  6. high pTcharged particle spectra Expected reach (0.5 nb-1): pT~ 300 GeV/c (inclusive hadrons)

  7. Jet Jet ET distributions for 1 month data Jet ET reco resolution

  8. Expected quarkonia signalsin one month data (di-muon) J. Phys. G: Nucl. Part. Phys. 34 (2007) 2307-2455 Assuming no quarkonia suppression Acceptance Solid line: Both μ |η|<2.4 dashed line: Both μ |η|<0.8

  9. (arbitrary) Stat. errors of Y’/Y ratios Curves are calculations for different initial conditions and different assumption of Tdiss

  10. Z0μμ signal 1 month data: ~11000 (Z μμ) J. Phys. G: Nucl. Part. Phys. 34 (2007) 2307-2455

  11. Tagged Jet An ideal way to measure parton energy loss in the medium

  12. Other interesting observables • Open charm & bottom • DK+π • DK+μ+νμ (K μ correlations) • B+J/psi K+ (BR~0.001) • B0J/psi K0 (BR~0.001) • X-section and flow are both very interesting • Z boson reconstruction • Ze+e- (BR 3.4%) • ZJets

  13. For B and D reconstruction • Low pt track efficiency is not bad • Ks can be reconstructed nicely • dEdx can help on PID pion efficiencies in pp and PbPb collisions Ks in pp Pixel+tracker

  14. DK+e+νe(K e correlations at STAR) PYthia simulation at 200 GeV 3<pT(e)<6 GeV/c 3<pT(e)<6 GeV/c Φ<36 degree

  15. DK+e+νe(K e correlations at STAR) Run5 & Run6 pp data

  16. Z boson reconstruction • Ze+e- (BR 3.4%) • Large energy electrons (>50 GeV) identification should be easy • ZJets • Huge background • Depends on the study of the jet reco algorithm

  17. LHC schedule • Preparing for mid-November start of beam operations • A few weeks for first collisions from then • First 7 TeV collisions in week before Christmas break • Initial operations at 7 TeV (3.5+3.5) • “Energy scan” (0.9, 7, 8-10TeV) • Pb+Pb run still scheduled at the end of p+p run • Now foreseen to start Nov 1 2010

  18. Thank you

  19. pp@14TeV L~1034cm-2s-1 PbPb@5.5TeV L~1027cm-2s-1 CMS detectors • Silicon pixel detector • Silicon microstrip tracker • Electromagnetic Calorimeter • Hadronic Calorimeter • Superconducting Solenoid • Muon detectors • Drift Tubes (barrel) • Cathode Strip Chambers (endcaps) • Resistive Plate Chambers (barrel+endcaps) • CASTOR Calorimeter • Zero Degree Calorimeter (Jet with cone R=0.5)

  20. Photon tagged jets CMS NOTE HIN-07-002 Quenched FF Unquenched FF models used in this analysis PYQUEN: selected QCD channels w/ jet quenching PYTHIA: selected QCD channels w/o jet quenching HYDJET: underlying corresponding Pb+Pb events Isolated photon + away side jet Ratio of quenched and unquenched FF Detailed quantitative studies of medium-induced parton energy-loss possible.

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