Chemical freeze-out parameters in Beam Energy Scan Program of STAR at RHIC

TL;DR

This paper analyzes the chemical freeze-out parameters in Au+Au collisions across various energies from the STAR Beam Energy Scan, revealing how these parameters depend on collision energy and centrality.

Contribution

It provides the first comprehensive extraction of chemical freeze-out parameters across multiple energies in the STAR BES-I program using a statistical model.

Findings

Chemical freeze-out temperature varies with collision energy.

Baryon chemical potential decreases as energy increases.

Particle ratios show clear energy dependence.

Abstract

The STAR experiment at RHIC has completed its first phase of the Beam Energy Scan (BES-I) program to understand the phase structure of the quantum chromodynamics (QCD). The bulk properties of the system formed in Au+Au collisions at different center of mass energy $\sqrt{s_{NN}} = $ 7.7, 11.5, 19.6, 27, and 39 GeV have been studied from the data collected in the year 2010 and 2011. The centrality and energy dependence of mid-rapidity ($|y|$ < 0.1) particle yields, and ratios are presented here. The chemical freeze-out parameters are extracted using measured particle ratios within the framework of a statistical model.