QCD phase transition and equation of state of stellar strong interaction matter via Dyson-Schwinger equation approach

TL;DR

This paper investigates the phase transition and equation of state of dense QCD matter using Dyson-Schwinger equations, incorporating a chemical potential dependent gluon model, and explores implications for compact star properties.

Contribution

It introduces a chemical potential dependent modification to the gluon model within Dyson-Schwinger equations to better describe phase transitions in dense QCD matter.

Findings

The modification reduces the chemical potential for phase coexistence.

No phase transition occurs with the unmodified Gaussian gluon model.

The maximum mass of compact stars is unaffected by the hadron-quark phase transition.

Abstract

We study the phase structure and phase transition of cold dense QCD matter via the Dyson-Schwinger equation approach. We take the rainbow approximation and the Gaussian-type gluon model. In order to guarantee that the quark number density begins to appear at the nuclear liquid-gas phase transition chemical potential, we propose a chemical potential dependent modification factor for the gluon model. We find that for the iso-symmetric quark matter, the modification reduces the chemical potential of the phase coexistence region of the first--order phase transition. We also implement the relativistic mean field theory to describe the hadron matter, and make use of the Maxwell and Gibbs construction method to study the phase transition of beta--equilibrium and charge neutral matter in compact stars. The results show that the phase transition will not happen in case of the Gaussian--type gluon model without any modification. The results also indicate that the upper boundary of the coexistence region should be larger than the current Nambu solution existing region. We also calculate the mass-radius relation of the compact stars, and find that the hadron-quark phase transition happens at too high chemical potential so that the maximum mass of the compact star is hardly affected by the hadron-quark phase transition.