ENTROPY SCALING IN ION–ION COLLISIONS AT AGS AND SPS ENERGIES

Abstract

Analysis of the experimental data on nucleus–nucleus collisions at AGS and SPS energies reveals that entropy produced in a limited and full phase-space increases with increasing beam energy and mass of the colliding nuclei. The analysis of the data and corresponding mixed event samples, carried out by considering the particles emitted in the forward and backward hemispheres separately, indicates the presence of clusterization and correlations amongst the produced particles. It is also observed that the total entropy produced in a limited pseudorapidity bin, when normalized to the maximum rapidity in the center of mass frame, is essentially independent of projectile and target masses as well as beam energy, indicating thereby presence of a kind of entropy scaling. The observed scaling is also nicely reproduced by the Monte Carlo models, AMPT and FRITIOF. Furthermore, results of the analysis of the mixed events reveal that the observed entropy scaling is a distinguishable feature of the data rather than a manifestation of the statistics.