Effects of equilibrium coexisting phases in the first-order chiral transition within the Linear sigma model with quarks

TL;DR

This paper investigates how equilibrium coexisting phases influence the nature of the first-order chiral transition in quark matter within the Linear sigma model, highlighting effects on sound speed and susceptibilities.

Contribution

It explores the impact of multiple conserved charges on the chiral transition, revealing potential continuous changes and novel effects on bulk properties.

Findings

Coexistence of equilibrium phases can alter the transition from discontinuous to continuous.

Multiple conserved charges significantly affect the speed of sound in quark matter.

Susceptibilities exhibit notable changes due to phase coexistence.

Abstract

The first order chiral phase transition for quark matter with flavor imbalance is studied using the Linear sigma model with quarks, also known as Quark-meson model. Special attention is paid to the role of the scalar isovector meson. The general consensus presently is that the chiral transition changes from a smooth crossover to first-order at low temperatures. This transition is assumed to be discontinuous, with unstable or metastable intermediate states. However, if multiple charges are simultaneously conserved the system could undergo a continuous change through a coexistence of equilibrium states. Under such assumption the bulk properties are analyzed and several remarkable effects for the speed of sound and the susceptibilities are stressed.