QCD equation of state and the structure of neutron stars in NJL model

TL;DR

This paper investigates the phase transitions of dense QCD matter using the NJL model, calculates the equation of state, and predicts neutron star properties consistent with recent astrophysical observations.

Contribution

It introduces a NJL model-based approach fitted to lattice QCD data to study QCD phase transitions and neutron star structure.

Findings

First order chiral phase transition at high chemical potential

Equation of state consistent with observed neutron star masses and radii

Predicted neutron star mass-radius relation aligns with recent data

Abstract

The chiral and pion superfluidity phase transitions are studied within NJL model. The model parameters are fitted by pion mass and decay constant together with recent isospin density from lattice QCD. The dense and cold QCD matter suffered the first order chiral phase transition during the quark chemical potential increase. Based on the studies of phase structures, the equation of states~(EoS) of dense QCD matter are calculated with the conditions of $\beta$ equilibrium and electric charge neutrality. Take the EoS as input, the mass-radius relation of neutron stars are predicted, which is consistent with recent observations of heaviest mass and radius of $1.4M_\odot$.