Systematics of chemical freeze-out parameters in heavy-ion collision experiments

Abstract

We discuss systematic uncertainties in the chemical freeze-out parameters from the $\chi^2$ analysis of hadron multiplicity ratios in the heavy-ion collision experiments. The systematics due to the choice of specific hadron ratios are found to lie within the experimental uncertainties. The variations obtained by removing the usual constraints on the conserved charges show similar behavior. The net charge to net baryon ratios in such unconstrained systems are commensurate with the expected value obtained from the protons and neutrons of the colliding nuclei up to the center of mass energies $\sim 40$ GeV. Beyond that the uncertainties in this ratio gradually increases, possibly indicating the reduction in baryon stopping.