Dynamical Fluctuations in Baryon--Meson Ratios

TL;DR

This paper investigates how dynamical fluctuations in baryon--meson ratios depend on collision energy, suggesting a connection to phase transition effects and modifying the hadron resonance gas model to match experimental data.

Contribution

It introduces a modified hadron resonance gas model incorporating phase transition effects and phase space modifications to accurately reproduce fluctuation data across energies.

Findings

Model successfully reproduces fluctuation data over all energies studied.

Phase space volume changes are linked to the hadron-quark-gluon plasma transition.

Modified model accounts for experimental acceptance and quark phase space occupation.

Abstract

The event-by-event dynamical fluctuations in kaon-to-proton and proton-to-pion ratios have been studied in dependence on center--of--mass energies of nucleon--nucleon collisions $\sqrt{s}$. Based on changing phase space volume which apparently is the consequence of phase transition from hadrons to quark--gluon plasma at large $\sqrt{s}$, the single--particle distribution function $f$ is assumed to be rather modified. Varying $f$ and phase space volume are implemented in the grand--canonical partition function, especially at $\sqrt{s}>17$ GeV, so that hadron resonance gas model, when taking into account the experimental acceptance ${\cal A}$ and quark phase space occupation factor $\gamma$, turns to be able to reproduce the dynamical fluctuations in $(K^++K^-)/(p+\overline{p})$ and $(p+\overline{p})/(\pi^++\pi^-)$ ratios over the entire range of $\sqrt{s}$.