Hybrid neutron stars with the Dyson-Schwinger quark model and various quark-gluon vertices

TL;DR

This study models cold dense quark matter and hybrid neutron stars using the Dyson-Schwinger approach, exploring how different quark-gluon vertices influence the phase transition, equation of state, and star properties.

Contribution

It introduces a comprehensive analysis of the impact of various quark-gluon vertices on the properties of hybrid neutron stars within the Dyson-Schwinger framework.

Findings

Vertex choice affects the effective interaction at finite chemical potential.

Phase transition and star properties mainly depend on the overall reduction of the effective interaction.

Results are insensitive to the specific vertex ansatz used.

Abstract

We study cold dense quark matter and hybrid neutron stars with a Dyson-Schwinger quark model and various choices of the quark-gluon vertex. We obtain the equation of state of quark matter in beta equilibrium and investigate the hadron-quark phase transition in combination with a hadronic equation of state derived within the Brueckner-Hartree-Fock many-body theory. Comparing with the results for quark matter with the rainbow approximation, the Ball-Chiu ansatz and the 1BC ansatz for the quark-gluon vertex lead to a reduction of the effective interaction at finite chemical potential, qualitatively similar to the effect of our gluon propagator. We find that the phase transition and the equation of state of the quark or mixed phase and consequently the resulting hybrid star mass and radius depend mainly on a global reduction of the effective interaction due to effects of both the quark-gluon vertex and gluon propagator, but are not sensitive to the vertex ansatz.