Measurements of π^±, K^±, p and p̅ spectra in ^40Ar+^45Sc collisions at 13A to 150A GeV/c

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 π^±, K^±, p and p̅ produced in ^40Ar+^45Sc collisions at beam momenta of 13A, 19A, 30A, 40A, 75A and 150A . The analysis uses the 10% most central collisions, where the observed forward energy defines centrality. The energy dependence of the K^±/π^± ratios as well as of inverse slope parameters of the K^± 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.