The inclusive transverse momentum (pT) distributions of primary charged particles are measured in the pseudo-rapidity range |η| < 0.8 as a function of event centrality in Pb–Pb collisions at √sNN = 2.76 TeV with ALICE at the LHC. The data are presented in the pT range 0.15 < pT < 50 GeV/c for nine centrality intervals from 70–80% to 0–5%. The results in Pb–Pb are presented in terms of the nuclear modification factor RAA using a pp reference spectrum measured at the same collision energy. We observe that the suppression of high-pT particles strongly depends on event centrality. The yield is most suppressed in central collisions (0–5%) with RAA ≈ 0.13 at pT = 6–7 GeV/c. Above pT = 7 GeV/c, there is a significant rise in the nuclear modification factor, which reaches RAA ≈ 0.4 for pT > 30 GeV/c. In peripheral collisions (70–80%), only moderate suppression (RAA =0.6–0.7) and a weak pT dependence is observed. The measured nuclear modification factors are compared to other measurements and model calculations.

Centrality dependence of charged particle production at large transverse momentum in Pb–Pb collisions at √SNN = 2.76 TeV

DE CARO, ANNALISA;DE GRUTTOLA, DANIELE;DE PASQUALE, Salvatore;FUSCO GIRARD, Mario;PAGANO, PAOLA;VIRGILI, Tiziano;
2013

Abstract

The inclusive transverse momentum (pT) distributions of primary charged particles are measured in the pseudo-rapidity range |η| < 0.8 as a function of event centrality in Pb–Pb collisions at √sNN = 2.76 TeV with ALICE at the LHC. The data are presented in the pT range 0.15 < pT < 50 GeV/c for nine centrality intervals from 70–80% to 0–5%. The results in Pb–Pb are presented in terms of the nuclear modification factor RAA using a pp reference spectrum measured at the same collision energy. We observe that the suppression of high-pT particles strongly depends on event centrality. The yield is most suppressed in central collisions (0–5%) with RAA ≈ 0.13 at pT = 6–7 GeV/c. Above pT = 7 GeV/c, there is a significant rise in the nuclear modification factor, which reaches RAA ≈ 0.4 for pT > 30 GeV/c. In peripheral collisions (70–80%), only moderate suppression (RAA =0.6–0.7) and a weak pT dependence is observed. The measured nuclear modification factors are compared to other measurements and model calculations.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11386/3994262
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