Update on p- Pb and Pb-Pb spectra
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Transcript of Update on p- Pb and Pb-Pb spectra
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Spectra in p-Pb collisionsp 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.
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Spectra in p-Pb collisionsTotal 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
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Spectra in p-Pb collisions: tracking efficiency
Tracking efficiency convoluted with the detector acceptance in the required rapidity range
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Spectra in Pb-Pb collisions: tracking efficiency
Tracking efficiency convoluted with the detector acceptance in the required rapidity range(MC prod. : LHC12a17a_fix)
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Spectra in Pb-Pb collisions: pions (0-50 % centr.)
Corrected spectra
PRELIMINARY
Centrality bins:0 – 5 %5 – 10 %10 – 20 %20 – 30 %30 – 40 %40 – 50 %
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Spectra in Pb-Pb collisions: kaons (0-50 % centr.)
Corrected spectra
PRELIMINARY
Centrality bins:0 – 5 %5 – 10 %10 – 20 %20 – 30 %30 – 40 %40 – 50 %
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Spectra in Pb-Pb collisions: kaons (0-50 % centr.)
Corrected spectra
PRELIMINARY
Centrality bins:0 – 5 %5 – 10 %10 – 20 %20 – 30 %30 – 40 %40 – 50 %
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Conclusions
• Pb-Pb corrected spectra have been evaluated in central and semi-central collisions (0-50%).
• 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).
• To do: • Further increase Monte Carlo statistic for PID efficiency
evaluation?• Cross check PID efficiency from MC with that extracted from real
data (V0’s decays).• Estimate feed-down correction.
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Spectra in Pb-Pb collisions: pions raw yields
Centrality bins:0 – 5 %5 – 10 %10 – 20 %20 – 30 %30 – 40 %40 – 50 %
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Spectra in Pb-Pb: kaons raw yields
Centrality bins:0 – 5 %5 – 10 %10 – 20 %20 – 30 %30 – 40 %40 – 50 %
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Spectra in Pb-Pb collsions: protons raw yields
Centrality bins:0 – 5 %5 – 10 %10 – 20 %20 – 30 %30 – 40 %40 – 50 %