Quark matter in high-mass neutron stars?

TL;DR

This paper investigates whether neutron stars with masses around 2 solar masses can contain deconfined quark matter in their cores, using a combined hadronic and quark matter equation of state.

Contribution

It introduces a quark matter model based on the Nambu--Jona-Lasinio framework and demonstrates compatibility with high-mass neutron star observations.

Findings

2 solar mass neutron stars can host deconfined quark matter

The combined equation of state supports hybrid star configurations

Quark matter presence does not preclude high neutron star masses

Abstract

The recent measurements of the masses of the pulsars PSR J1614-2230 and PSR J0348-0432 provide independent proof for the existence of neutron stars with masses in range of 2 $M_\odot$. This fact has significant implications for the physics of high density matter and it challenges the hypothesis that the cores of NS can be composed of deconfined quark matter. In this contribution we study a description of quark matter based on the Nambu--Jona-Lasinio effective model and construct the equation of state for matter in beta equilibrium. This equation of state together with the hadronic Dirac-Brueckner-Hartree-Fock equation of state is used here to describe neutron star and hybrid star configurations. We show that compact stars masses of 2 $M_\odot$ are compatible with the possible existence of deconfined quark matter in their core.