A Study of the QCD Critical Point Using Particle Ratio Fluctuations

TL;DR

This paper investigates fluctuations in particle ratios near the QCD critical point, using new measurements from RHIC to explore energy dependence in heavy-ion collisions, aiming to identify signatures of critical phenomena.

Contribution

It provides new experimental data on $K/\pi$ and $p/\pi$ ratio fluctuations across multiple energies, extending the search for the QCD critical point at RHIC.

Findings

Observed energy dependence of dynamical fluctuations.

Compared results with theoretical models.

Extended the measurement range to lower energies.

Abstract

Dynamical fluctuations in global conserved quantities such as baryon number, strangeness, or charge may be observed near a QCD critical point. Results from new measurements of dynamical $K/\pi$ and $p/\pi$ ratio fluctuations are presented. The commencing of a QCD critical point search at RHIC has extended the reach of possible measurements of dynamical $K/\pi$ and $p/\pi$ ratio fluctuations from Au+Au collisions to lower energies. The STAR experiment has performed a comprehensive study of the energy dependence of these dynamical fluctuations in Au+Au collisions at the energies $\sqrt{s_{NN}}$ = 7.7, 11.5, and 39 GeV. New results are compared to previous measurements and to theoretical predictions from several models.