Quarkyonic matter state of neutron stars

TL;DR

This paper investigates quarkyonic matter in neutron star cores, modeling isospin effects with mesons, and compares theoretical predictions with observational data on neutron star properties.

Contribution

It extends previous quarkyonic matter models to neutron-rich matter, incorporating isospin interactions and analyzing their impact on neutron star characteristics.

Findings

Pressure and tidal deformability match observational constraints.

Mass-radius relation fails to reach two solar masses.

Model incorporates isospin effects via $ ho$ mesons.

Abstract

This work extends our previous study of isospin symmetric quarkyonic matter to quarkyonic neutron matter which might be relevant to the inner cores of neutron stars. The vector-isovector $\rho$ mesons are introduced to the model mainly to account for isospin density interactions, just like $\omega$ meson for baryon density interactions. The modified Lagrangian still preserves approximate chiral symmetry which could be significantly broken at lower density. And new free parameters are fixed by adopting the experimental constraints on the symmetry energy and its slope at saturation density. Eventually, the pressure, mass-radius relation, and tidal deformability are explored in advance for the quarkyonic neutron stars. While the pressure and tidal deformability are well consistent with experimental and observational restrictions, the mass-radius relation is unable to reproduce the observed two solar mass of PSR J0740+6620.