Three-body couplings in RMF and its effects on hyperonic star equation of state

TL;DR

This paper introduces a new relativistic mean field model with explicit three-body couplings to better understand hyperonic matter in neutron stars, addressing the challenge of supporting massive neutron stars with hyperons.

Contribution

The paper develops a novel RMF model incorporating three-body couplings and adjusts hyperon vector couplings, providing a consistent explanation for massive neutron stars and hypernuclear data.

Findings

Three-body couplings stiffen the EOS for hyperonic matter.

Modified hyperon vector couplings align model predictions with observations.

The model supports neutron stars with masses around two solar masses.

Abstract

We develop a new relativistic mean field (RMF) model including explicit three-body couplings and apply it to hyperonic systems and neutron star matter. The recent observation of the massive mass neutron star has given us a puzzle; when strange hadrons including hyperons are taken into account, the equation of state (EOS) becomes too soft to support the observed two-solar-mass neutron star. Three-baryon repulsion is a promising ingredient to answer this puzzle. We demonstrate that it is possible to consistently explain the massive neutron star and hypernuclear data when we include three-body couplings and modify the hyperon vector couplings from the flavor SU(3) values.