The temperatures of protons andπ − mesons in central nucleus-nucleus interactions at a momentum of 4.5 GeV/c per incident nucleon

Abstract

An estimate of the temperature of protons andπ − mesons in central He−Li, He−C, C−C, C−Ne, C−Cu, C−Pb, O−Pb, Mg−Mg interactions is presented. The results indicate an increase of the proton temperature with increasing mass numbers of projectile and target nuclei (A p ,A T ) fromT p =(118±3) MeV for He−Li toT p =(141±2) MeV for C−Pb. The temperature ofπ − mesons does not depend onA P ,A T andT π ≃95 MeV. A satisfactory fit forπ − mesons in C−Cu, C−Pb, O−Pb, Mg−Mg collisions can be achieved by using a form involving two temperatures,T 1 andT 2. The relative yield of the high temperature component (T 2) is ≅24% for C−Cu, C−Pb, and Mg−Mg interactions. The observed results forT P in C−Ne, C−Cu and C−Pb collisions are consistent with the prediction of the thermodynamic hagedorn model.