Centrality dependence of charged particle production at large transverse momentum in Pb–Pb collisions at sqrt(s_NN)=2.76 TeV

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.