Strangeness production and nuclear modification at LHC energies

Abstract

We report results on strangeness production in Pb–Pb collisions at sNN=2.76 TeV, p-Pb collisions at sNN=5.02 TeV and pp collisions at s=7 TeV from the ALICE collaboration. In heavy-ion collisions, the nuclear modification factor RAA of charged pions, kaons and protons shows a strong, centrality dependent suppression with respect to pp collisions. RAA for Ξ is similar to the one for protons. In 0–10% central collisions, RAA for Ω is significantly higher than RAA for Ξ and exceeds unity. The hyperon-to-pion yields measured in pp collisions as a function of the pseudorapidity density of primary charged particles at midrapidity exhibit a pronounced multiplicity dependence similar to p–Pb collisions. The production rate of strange particles increases faster with multiplicity than that of non-strange hadrons. No enhancement is observed for particles with no strange quark content, demonstrating that the observed effect is strangeness rather than mass related.