Measuring Dynamical K/$\pi$ and p/$\pi$ Fluctuations in Au+Au Collisions from the STAR Experiment

TL;DR

This paper reports new measurements of dynamical K/π and p/π ratio fluctuations in Au+Au collisions at various energies, aiming to identify signals of the QCD critical point and comparing results with theoretical models.

Contribution

It provides the first measurements of these fluctuations at lower energies and compares them with previous data and UrQMD model predictions.

Findings

Dynamical fluctuations vary with collision energy.

Results are consistent with some theoretical predictions.

No definitive critical point signal observed.

Abstract

Results from new measurements of dynamical $K/\pi$ and $p/\pi$ ratio fluctuations are presented. Dynamical fluctuations in global conserved quantities such as baryon number, strangeness, or charge may be observed near a QCD critical point. The STAR experiment has previously acquired data in Au+Au collisions at the energies $\sqrt{s_{NN}}$ = 200, 130, 62.4, and 19.6 GeV and Cu+Cu collisions at $\sqrt{s_{NN}}$ = 200, 62.4, and 22.4 GeV. 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. New results are compared to previous measurements and to theoretical predictions from the UrQMD model.