Mean pion multiplicities in Ar+Sc collisions

TL;DR

This paper reports on measurements of mean negatively charged pion multiplicities in central Ar+Sc collisions at various energies, using the NA61/SHINE detector, and compares these results with other experiments to analyze energy and system size dependence.

Contribution

It introduces a method to determine total pion multiplicities from rapidity distributions and compares results with other data, highlighting system and energy dependence.

Findings

Pion multiplicities increase with collision energy.

Results are consistent with existing data across different systems.

The ratio of pions to wounded nucleons varies with energy.

Abstract

Preliminary results for mean negatively charged pion multiplicities $\langle \pi^- \rangle$ using the $h^-$ method are presented for central Ar+Sc collisions at 13, 19, 30, 40, 75 and 150\textit{A} GeV/c beam momentum. The data were recorded by the NA61/SHINE detector at the CERN SPS. Starting with rapidity distributions ${dn}/{dy}$ the procedure of obtaining total multiplicities is presented. The mean number of wounded nucleons $\langle W\rangle$ extracted from the Glissando MC model is used to calculate the ratio $\langle \pi^- \rangle/\langle W\rangle.$ The results are compared to those from other experiments and their dependence on colliding systems and collision energy is discussed.