The Phase Diagram of Hadronic Matter

TL;DR

This paper explores the phase transitions of hadronic matter using percolation theory, identifying two main regimes based on density and comparing results with chiral models.

Contribution

It introduces a geometrical and dynamical interpretation of hadronic phase transitions using percolation theory, highlighting two distinct regimes at different densities.

Findings

Identification of phase transition as a percolation process

Distinction between low and high baryon density regimes

Comparison with effective chiral model results

Abstract

We interpret the phase structure of hadronic matter in terms of the basic dynamical and geometrical features of hadrons. Increasing the density of constituents of finite spatial extension, by increasing the temperature T or the baryochemical potential mu, eventually "fills the box" and eliminates the physical vacuum. We determine the corresponding transition as function of T and mu through percolation theory. At low baryon density, this means a fusion of overlapping mesonic bags to one large bag, while at high baryon density, hard core repulsion restricts the spatial mobility of baryons. As a consequence, there are two distinct limiting regimes for hadronic matter. We compare our results to those from effective chiral model studies.