Production of charged pions, kaons and protons at large transverse momenta in pp and Pb-Pb collisions at \(\sqrt{s_{NN}}\) = 2.76 TeV

Abstract

Transverse momentum spectra of \(\pi^{\pm}, K^{\pm}\) and \(p(\bar{p})\) up to \(p_T\) = 20 GeV/c at mid-rapidity, |y| \(\le\) 0.8, in pp and Pb-Pb collisions at \(\sqrt{s_{NN}}\) = 2.76 TeV have been measured using the ALICE detector at the LHC. At intermediate \(p_T\) (2-8 GeV/c) an enhancement of the proton-to-proton ratio, (p + \(\bar{p})/(\pi^+ + \pi^-\(), with respect to pp collisions is observed and the ratio reaches 0.80 in central Pb-Pb collisions. The measurement of the nuclear modification factors for \(\pi^{\pm}, K^{\pm}\) and \(p(\bar{p})\) indicates that within the systematic and statistical uncertainties they are the same at high \(p_T\) (> 10 GeV/c), suggesting that the chemical composition of leading particles from jets in the medium is similar to that of vacuum jets.