Nuclear symmetry energy in a modified quark meson coupling model

TL;DR

This paper investigates nuclear symmetry energy and related instabilities using a modified quark-meson coupling model, deriving an analytic expression and exploring implications for neutron star radii.

Contribution

It introduces a modified quark-meson coupling model with an averaged confining potential and derives an analytic symmetry energy expression linking it to its slope.

Findings

Established a linear correlation between symmetry energy slope L and symmetry energy ${ m E}_{sym}$.

Provided an analytic expression for symmetry energy as a function of its slope.

Analyzed neutron star radius constraints in beta-equilibrated matter.

Abstract

We study nuclear symmetry energy and the thermodynamic instabilities of asymmetric nuclear matter in a self-consistent manner by using a modified quark-meson coupling model where the confining interaction for quarks inside a nucleon is represented by a phenomenologically averaged potential in an equally mixed scalar-vector harmonic form. The nucleon-nucleon interaction in nuclear matter is then realized by introducing additional quark couplings to $\sigma$, $\omega$, and $\rho$ mesons through mean-field approximations. We find an analytic expression for the symmetry energy ${\cal E}_{sym}$ as a function of its slope $L$. Our result establishes a linear correlation between $L$ and ${\cal E}_{sym}$. We also analyze the constraint on neutron star radii in $(pn)$ matter with $\beta$ equilibrium.