Hyperon and nuclear symmetry energy in the neutron star

TL;DR

This paper investigates how nuclear symmetry energy and hyperons influence neutron star properties like mass and radius using a relativistic mean field model with density-dependent couplings.

Contribution

It introduces a model incorporating hyperons and recent symmetry energy data to analyze their combined effects on neutron star observables.

Findings

Hyperons significantly affect neutron star mass-radius relations.

Density-dependent symmetry energy impacts the maximum mass of neutron stars.

Hyperon presence can soften the equation of state, reducing star radii.

Abstract

In this work, masses and radii of neutron stars are considered to investigate the effect of nuclear symmetry energy to the astrophysical observables. A relativistic mean field model with density-dependent meson-baryon coupling constants is employed in describing the equation of state of dense nuclear matter, and the density dependencies of the symmetry energies are quoted from the recent phenomenological formulae obtained from the heavy ion data at subnuclear saturation densities. Since hyperons can take part in the $\beta$-equilibrium of the dense matter inside neutron stars, we include hyperons in our estimation and their roles are discussed in combination with that of the nuclear symmetry energy.