Equation of state for neutron stars in SU(3) flavor symmetry

TL;DR

This paper investigates the equation of state for neutron stars using relativistic models with SU(3) flavor symmetry, showing how strange mesons and baryon structure influence maximum mass and stability.

Contribution

It extends relativistic mean field models to SU(3) flavor symmetry, incorporating strange mesons to better understand neutron star properties and hyperon effects.

Findings

Equation of state supports neutron stars up to 2.1 solar masses.

Strange mesons significantly affect the star's maximum mass.

SU(3) symmetry allows hyperons without collapsing the star.

Abstract

Using several relativistic mean field models (such as GM1, GM3, NL3, TM1, FSUGold and IU-FSU) as well as the quark-meson coupling model, we calculate the particle fractions, the equation of state, the maximum mass and radius of a neutron star within relativistic Hartree approximation. In determining the couplings of the isoscalar, vector mesons to the octet baryons, we examine the extension of SU(6) spin-flavor symmetry to SU(3) flavor symmetry. Furthermore, we consider the strange ($\sigma^{\ast}$ and $\phi$) mesons, and study how they affect the equation of state. We find that the equation of state in SU(3) symmetry can sustain a neutron star with mass of $(1.8 \sim 2.1) M_{\odot}$ even if hyperons exist inside the core. In addition, the strange vector ($\phi$) meson and the variation of baryon structure in matter also play important roles in supporting a massive neutron star.