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R AA and R CP of single muons from heavy quark and vector boson decays at the LHC

Workshop on Predictions for LHC, CERN, May 29 – June 2, 2007. R AA and R CP of single muons from heavy quark and vector boson decays at the LHC. Z.Conesa del Valle 1 , A.Dainese 2 , H.-T.Ding 3 , G.Martinez 1 , D.Zhou 3 1 Subatech Nantes, 2 INFN Legnaro, 3 CCNU Wuhan.

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R AA and R CP of single muons from heavy quark and vector boson decays at the LHC

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  1. Workshop on Predictions for LHC, CERN, May 29 – June 2, 2007 RAA and RCP of single muons from heavy quark and vector boson decays at the LHC Z.Conesa del Valle1, A.Dainese2, H.-T.Ding3, G.Martinez1, D.Zhou3 1Subatech Nantes, 2INFN Legnaro, 3CCNU Wuhan thanks to N.Armesto, C.Salgado, U.Wiedemann LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  2. The Key Point:m’s from W as a medium-blind reference • pQCD predicts b/W crossing at ptmuon ~ 30 GeV/c • m from W should be unaffected by the medium • b-quark energy loss would shift crossing to lower pt • How would the muon RAA / RCP look like? LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  3. LHC Experiments: Muon Acceptance • ALICE muon spectrometer: -4 <h< -2.5 and pt >1 GeV/c • CMS, ATLAS: |h| < 2.5 and pt > 3.5 GeV/c • High pt reach in Pb-Pb: about 70-80 GeV/c LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  4. Baseline spectra Heavy quarks: • Quark-level baseline: c and b quark single-inclusive d2s/dpTdy from MNR code (NLO pQCD) • parameters: mc=1.2 GeV, mF=mR=2mT,c, mb=4.75 GeV, mF=mR=mT,b, CTEQ4M PDFs (with EKS98 for Pb-Pb) • Peterson fragmentation function (with ymeson = yQ) • e parameter from HERA-LHC Workshop proceedings (M.Corradi) • ec=0.02, eb=0.001 (from to LEP data) • Decay of meson to muon using spectator model • e.g. m kinematics for Bm from bc+m+nm Vector bosons: • PYTHIA (reproduces W cross section at Tevatron) • Cross section normalized to NLO results (Frixione-Mangano, Vogt) • more details in: Z.Conesa del Valle et al. ALICE-INT-2006-021 MNR code: Mangano, Nason, Ridolfi, NPB373 (1992) 295 Eskola, Kolhinen, Salgado, EPJC 9 (1999) 61 HERA-LHC Proceedings, CERN/LHCC 2005-014, hep-ph/0601164 Frixione, Mangano, hep-ph/0405130; Vogt, hep-ph/0011242 LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  5. Total single-muon spectrum in Pb-Pbwithout E loss ALICE muon spectrometer acc.: -4 < h < -2.5, pt > 1 GeV, p > 4 GeV LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  6. Effect of shadowing (EKS98) in Pb-Pb -4 < h < -2.5 W beauty charm total LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  7. Effect of shadowing (EKS98) in Pb-Pb -4 < h < -2.5 just an indication (PYTHIA LO): W beauty charm total -4 < h < -2.5 -4 < h < -2.5 LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  8. Effect of shadowing (EKS98) in Pb-Pb -4 < h < -2.5 ALICE muon spectrometer -4 < h < -2.5 val. q sea q gluon gluon W beauty charm total W 1.0*0.85=0.85 EKS98 sea q EKS98 val. q LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  9. EKS98 gluon EKS98 gluon Effect of shadowing (EKS98) in Pb-Pb -4 < h < -2.5 ALICE muon spectrometer -4 < h < -2.5 val. q sea q gluon gluon W beauty charm total b 0.95*1.05=1 LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  10. Heavy Quark Radiative E Loss  C.Salgado • Mass-dependent BDMPS quenching weights • Glauber collision geometry à la PQM • Transport coefficient for a static medium: Armesto, Dainese, Salgado, Wiedemann, PRD 71 (2005) 054027.  C.Loizides • EKRT Saturation model Eskola, Kajantie, Ruuskanen, Tuominen, NPB 570 (2000) 379. (corresponds to dNch/dy ~ 3000) LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  11. -15% negligible effect on muon suppression for |h| < 4 E loss for c and b VS rapidity Calculation of radiated energy: compute DE using Lt; quench pt; keep y constant. • Decrease of medium density at forward rapidity should be accounted for • Assumed , i.e. • using LHC multiplicity as predicted by D.Kharzeev, E.Levin, M.Nardi, hep-ph/0408050 (gives moderate density change for |h| < 4) pt Lt y LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  12. RCP (0-10%)/(40-70%) increases from 0.4 to 0.9 Effect of E loss in Pb-Pb 0-10% Crossing point shifts down by 5-7 GeV/c RAA increases from 0.3 to 0.8 Similar results in -4 < h < -2.5 LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  13. Effect of E loss in Pb-Pb 0-10%- b mass effect - RCP RAA thin: no mass effect thick: mass effect thin: no mass effect thick: mass effect LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  14. Summary • At LHC, high pt muon spectrum will be one of the first measurements sensitive to b quark energy loss • Crossing point of b and W muons shifts down by 5-7 GeV/c • RAA rapidly increases from 0.3 to 0.8 between 20 (b-dominated) and 40 GeV/c (W-dominated) LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  15. EXTRA SLIDES LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  16. BDm can be neglected: Baseline: m from c and b, no E loss MNR+Peterson+spectator model decay VS PYTHIA (ALICE tune) (from Z.Conesa) (from Z.Conesa) LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  17. m from b with E loss:effect of mass Effect of b-quark mass for ptmuon < 20-30 GeV/c LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  18. m from b with E loss:effect of dN/dh scaling for qhat In this model, the effect of density decrease at forward y is negligible within the MUON spectrometer acceptance LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  19. Effect of E loss in Pb-Pb- ALICE muon spectrometer - LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  20. LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  21. LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

  22. LHC Predictions Workshop, CERN, 01.06.2007 Andrea Dainese

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