First Measurement of the Strange Particles R CP Nuclear Modification Factors in Heavy-Ion Collisions at the SPS

Abstract

Abstract. The NA57 experiment has measured the p T distributions of K 0 S , Λ, and Λ particles in fixed-target Pb-Pb interactions at √ s NN = 17.3 GeV, as a function of the collision centrality. In this paper we study the central-toperipheral nuclear modification factors and compare them to other measurements and to theoretical predictions.