Massive neutron star with strangeness in a relativistic mean-field model with a high-density cut-off

TL;DR

This paper models massive neutron stars with strangeness using a relativistic mean-field approach incorporating a high-density cut-off, successfully explaining observed neutron star masses and hyperon effects.

Contribution

It introduces a logarithmic sigma-cut potential in the RMF model, enabling realistic neutron star masses with hyperons and high-density nucleon mass saturation.

Findings

Maximum neutron star mass exceeds two solar masses.

Hyperons are included with realistic coupling constants.

Nucleon mass saturates at high density.

Abstract

The properties of strangeness neutron star are studied within relativistic mean-field (RMF) model via including a logarithmic interaction as a function of scalar meson field. This logarithmic interaction, named as the $\sigma$-cut potential, can largely reduce the attractive contributions of scalar meson field at high density without any influence on nuclear structure around normal saturation density. In this work, the TM1 parameter set is chosen as the RMF interaction, while the strengths of logarithmic interaction are constrained by the properties of finite nuclei so that we can obtain a reasonable effective nucleon-nucleon interaction. The hyperons, $\Lambda,~\Sigma$, and $\Xi$ are also considered in neutron stars within this framework, whose coupling constants with mesons are determined by the latest hyperon-nucleon and $\Lambda$-$\Lambda$ potentials extracted from the experimental data of hypernuclei. The maximum mass of neutron star can be larger than two solar mass with these hyperons. Furthermore, the nucleon mass at high density will be saturated due to this additional $\sigma$-cut potential, which is consistent with the conclusions from the microscopic calculations such as, Brueckner-Hartree-Fock theory and quark mean-field model.