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HMPID weekly meeting. Update on p- Pb spectra. G. Volpe. 31/10/2013. Spectra in p- Pb collisions. p. Pb. proton beam energy = 4 TeV ; proton energy in lead nuclei = 4x82/208 ≈ 1.58 TeV ; Center of mass energy per nucleon pair = 2(4x1.58) 0.5 ≈ 5.02 TeV ;
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HMPID weekly meeting Update on p-Pb spectra G. Volpe 31/10/2013
Spectra in p-Pb collisions p Pb • proton beam energy = 4 TeV; • proton energy in lead nuclei = 4x82/208 ≈ 1.58 TeV; • Center of mass energy per nucleon pair = 2(4x1.58)0.5 ≈ 5.02 TeV; • The center of mass moves in the lab. frame with rapidity Y = - 0.465.
Spectra in p-Pb collisions • Total statistic • p-Pb 5.02 TeV, LHC13b (EDSs pass3): ≈ 20 millions MB events • p-Pb 5.02 TeV, LHC13c (ESDs pass2): ≈ 70 millions MB events • Centrality (multiplicity) selected using the amplitude of the signal of V0A detector; • Spectra evaluated in the rapidity range 0 < YCMS < 0.5; • YLAB = YCMS – 0.465, 0 < YCMS < 0.5 corresponds to -0.465 < YLAB < 0.035 • For each mass hypothesis a cut on YLAB has been applied and the corresponding raw yields has been evaluated. • The main corrections have been estimated from Monte Carlo: • MC productions: LHC13b2_efix_p1, LHC13b2_efix_p2
Spectra in p-Pb collisions: pions Corrected spectra PRELIMINARY
Spectra in p-Pb collisions: kaons Corrected spectra PRELIMINARY
Spectra in p-Pb collisions: protons Corrected spectra PRELIMINARY
Comparison HMPID spectra with combined spectra (ITS+TPC+TOF+rTPC): 0-5 %
Comparison HMPID spectra with combined spectra (ITS+TPC+TOF+rTPC): 5-10 %
Comparison HMPID spectra with combined spectra (ITS+TPC+TOF+rTPC): 10-20 %
Comparison HMPID spectra with combined spectra (ITS+TPC+TOF+rTPC): 20-40 %
Comparison HMPID spectra with combined spectra (ITS+TPC+TOF+rTPC): 40-60 %
Comparison HMPID spectra with combined spectra (ITS+TPC+TOF+rTPC): 60-80 %
Comparison HMPID spectra with combined spectra (ITS+TPC+TOF+rTPC): 80-100 %
Comparison HMPID spectra with combined spectra (ITS+TPC+TOF) Pions
Comparison HMPID spectra with combined spectra (ITS+TPC+TOF): kaon K+ Kaons
Comparison HMPID spectra with combined spectra (ITS+TPC+TOF): proton Protons p
Spectra in p-Pb collisions: pions & kaons < 4 GeV/c Verypreliminary Positive
Spectra in p-Pb collisions: pions & kaons < 4 GeV/c Verypreliminary Negative
Conclusions • p-Pb corrected spectra have been evaluated in all events classes (V0A 0-100%). • Main corrections have been applied (tracking eff., PID eff., distance cut). • Pions and kaons spectra pushed up to 4 GeV/c (very preliminary)!! • To do: • Further increase Monte Carlo statistic for tracking and PID efficiency evaluation? • Cross check PID efficiency from MC with that extracted from real data (V0’s decays). • Estimate GEANT-FLUKA and feed-down correction. • Systematic uncertanties.
Spectra in p-Pb collisions: tracking efficiency • Tracking efficiency convoluted with the detector acceptance in the required rapidity range; • MC productions: LHC13b2_efix_p1, LHC13b2_efix_p1, LHC13b2_efix_p3 • The corresponding correction is obtained by fitting such distributions