Fluctuations and correlations of baryonic chiral partners

TL;DR

This paper investigates the fluctuations and correlations of net-baryon number density in hot and dense hadronic matter using the parity doublet model, providing insights into critical phenomena and phase transitions relevant to QCD and heavy-ion collision experiments.

Contribution

It introduces a study of baryonic fluctuations and correlations near chiral phase transitions using the parity doublet model, highlighting qualitative properties and systematics.

Findings

Fluctuations of positive-parity nucleons do not always mirror total net-baryon fluctuations.

The structure of the correlator reveals non-trivial features near phase boundaries.

Differences are identified between fluctuations near chiral and liquid-gas phase transitions.

Abstract

Fluctuations and correlations of the net-baryon number play an important role in exploring critical phenomena in phase transitions of strongly interacting matter governed by Quantum chromodynamics (QCD). In this work, we use the parity doublet model to investigate the fluctuations of the net-baryon number density in hot and dense hadronic matter. The model accounts for chiral criticality within the mean-field approximation. We focus on the qualitative properties and systematics of the first- and second-order susceptibility of the net-baryon number density, and their ratios for nucleons of positive and negative parity, as well as their correlator. We show that the fluctuations of the positive-parity nucleon do not necessarily reflect the fluctuations of the total net-baryon number density at the phase boundary of the chiral phase transition. We also investigate the non-trivial structure of the correlator. Furthermore, we discuss and quantify the differences between the fluctuations of the net-baryon number density in the vicinity of the chiral and liquid-gas phase transition in nuclear matter. We indicate a possible relevance of our results with the interpretation of the experimental data on net-proton number fluctuations in heavy-ion collisions.