$\delta$ meson effects on neutron stars in the modified quark-meson coupling model

TL;DR

This study examines how including the $ ext{δ}$ meson in a modified quark-meson coupling model affects neutron star properties, revealing its impact on particle populations, equation of state, and maximum mass.

Contribution

It introduces the $ ext{δ}$ meson into the model and analyzes its effects on neutron star matter and structure, highlighting differences with or without hyperons.

Findings

$ ext{δ}$ meson increases neutron star maximum mass

It softens EOS with hyperons, stiffens without hyperons

$ ext{δ}$ meson influences hyperon populations and particle ratios

Abstract

The properties of neutron stars are investigated by including $\delta$ meson field in the Lagrangian density of modified quark-meson coupling model. The $\Sigma^-$ population with $\delta$ meson is larger than that without $\delta$ meson at the beginning, but it becomes smaller than that without $\delta$ meson as the appearance of $\Xi^-$. The $\delta$ meson has opposite effects on hadronic matter with or without hyperons: it softens the EOSes of hadronic matter with hyperons, while it stiffens the EOSes of pure nucleonic matter. Furthermore, the leptons and the hyperons have the similar influence on $\delta$ meson effects. The $\delta$ meson increases the maximum masses of neutron stars. The influence of $(\sigma^*,\phi)$ on the $\delta$ meson effects are also investigated.