An approach to chemical freeze-out scenario of identified particle spectra at 200AGeV Au-Au collisions at RHIC

TL;DR

This paper models the chemical freeze-out process in heavy-ion collisions at RHIC, using hydrodynamical calculations to describe particle spectra and the effects of chemical and thermal freeze-out on particle abundances.

Contribution

It introduces a hydrodynamical model that incorporates chemical freeze-out near the phase transition, improving the understanding of particle spectra in heavy-ion collisions.

Findings

Multi-strange hadrons freeze out chemically near the phase transition temperature.

The model reproduces particle spectra across different centralities.

Chemical freeze-out significantly corrects particle multiplicities, especially for multi-strange hadrons.

Abstract

Thermal model fit indicates early chemical freeze-out of multi-strange hadrons with small collective velocities at 200AGeV Au-Au collisions at RHIC. In this work, we present our recent results by SPheRIO hydrodynamical calculations inspired by this picture. In our model, multi-strange hadrons go through chemical freeze-out when the system reaches some temperature close to the phase transition, stopping to make inelastic collisions, and their abundances are therefore determined only by partonic EOS. At a lower temperature thermal freeze-out takes place where elastic collisions are brought to a halt. We calculate the spectra for various hadrons at different centrality windows, with chemical and thermal freeze-out temperature being fit as a function of centrality. As it is shown, the result provides a reasonable panoramic description of the spectra of identified particles. Chemical freeze-out gives good correction of the multiplicity of certain species of particles, especially for multi-strange hadrons.