Measurements of \(\pi ^\pm \), \(K^\pm \), p and \(\bar{p}\) spectra in \(^{40}\hbox {Ar+}^{45}\hbox {Sc}\) collisions at 13A to 150A \(\text{ Ge }\hspace{-1.00006pt}\text{ V }\!/\!c\)

Abstract

The NA61/SHINE experiment at the CERN Super Proton Synchrotron studies the onset of deconfinement in strongly interacting matter through a beam energy scan of particle production in collisions of nuclei of varied sizes. This paper presents results on inclusive double-differential spectra, transverse momentum and rapidity distributions and mean multiplicities of \(\pi ^\pm \), \(K^\pm \), p and \(\bar{p}\) produced in \(^{40}\hbox {Ar+}^{45}\hbox {Sc}\) collisions at beam momenta of 13A, 19A, 30A, 40A, 75A and 150A \(\text{ Ge }\hspace{-1.00006pt}\text{ V }\!/\!c\). The analysis uses the 10% most central collisions, where the observed forward energy defines centrality. The energy dependence of the \(K^\pm \)/\(\pi ^\pm \) ratios as well as of inverse slope parameters of the \(K^\pm \) transverse mass distributions are placed in between those found in inelastic \(p+p\) and central Pb + Pb collisions. The results obtained here establish a system-size dependence of hadron production properties that so far cannot be explained either within statistical or dynamical models.