News on mean pion multiplicity from NA61/SHINE

Abstract

NA61/SHINE is a large acceptance fixed target experiment at the CERN SPS which studies final hadronic states in interactions between various particles and nuclei [1]. The main topic of this contribution are preliminary results for mean negatively charged pion multiplicities 〈π−〉 from central Ar+Sc and Be+Be collisions. The data were taken recently by the NA61/SHINE collaboration for a wide range of beam momenta. Measured rapidity distributions dndy were extrapolated to unmeasured regions to obtain total multiplicities 〈π−〉 A new scheme to calculate the mean number of wounded nucleons 〈W〉 utilizing the EPOS MC model is described. Using data from other experiments, a comparison of 〈 π〉〈W〉for different collisions and beam momenta is discussed.