Update on p- Pb and Pb-Pb spectra

1. HMPID weekly meeting Update on p-Pb and Pb-Pb spectra G. Volpe CERN, 26/09/2013

2. p-Pb

3. 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.

4. 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

5. Spectra in p-Pb collisions: tracking efficiency Tracking efficiency convoluted with the detector acceptance in the required rapidity range

6. Spectra in p-Pb collisions: PID efficiency

7. Spectra in p-Pb collisions: distance cut correction

8. Spectra in p-Pb collisions: minimum bias Corrected spectra PRELIMINARY

9. Spectra in p-Pb collisions: pions Corrected spectra PRELIMINARY

10. Spectra in p-Pb collisions: kaons Corrected spectra PRELIMINARY

11. Spectra in p-Pb collisions: protons Corrected spectra PRELIMINARY

12. Pb-Pb

13. Spectra in Pb-Pb collisions: tracking efficiency Tracking efficiency convoluted with the detector acceptance in the required rapidity range (MC prod. : LHC12a17a_fix)

14. Spectra in Pb-Pb collisions: PID efficiency (0-5 % centr.)

15. Spectra in Pb-Pb collisions: PID efficiency (5-10 % centr.)

16. Spectra in Pb-Pb collisions: PID efficiency

17. Spectra in Pb-Pb collisions: distance cut correction

18. 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 %

19. 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 %

20. 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 %

21. Ratios

22. Hadron ratios in p-Pb data: anti-part/part

23. Hadron ratios in p-Pb data: K/p, p/p

24. Hadron ratios in Pb-Pb data: anti-part/part

25. Hadron ratios in Pb-Pb data: K/p, p/p

26. 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.

27. Backup

28. Spctra in Pb-Pb collisions: fit exapmples

29. Spectra in Pb-Pb collisions: pions raw yields Centrality bins: 0 – 5 % 5 – 10 % 10 – 20 % 20 – 30 % 30 – 40 % 40 – 50 %

30. Spectra in Pb-Pb: kaons raw yields Centrality bins: 0 – 5 % 5 – 10 % 10 – 20 % 20 – 30 % 30 – 40 % 40 – 50 %

31. Spectra in Pb-Pbcollsions: protons raw yields Centrality bins: 0 – 5 % 5 – 10 % 10 – 20 % 20 – 30 % 30 – 40 % 40 – 50 %

32. Spectra in p-Pb collisions: p/p ratio ITS+TPC+TOF HMPID