Hyperons in neutron star matter within relativistic mean-field models

TL;DR

This study investigates the presence of hyperons in neutron star cores using relativistic mean-field models, demonstrating the possibility of massive stars with hyperons and specific radii, while highlighting the importance of hyperon interactions.

Contribution

It provides a comprehensive parameter study showing that hyperons can coexist with high mass neutron stars, depending on hyperon interaction models.

Findings

High mass neutron stars with hyperons are possible.

Neutron star radii of 12-13 km at 1.4 solar masses are achievable.

Spinodal instability occurs at hyperon onset.

Abstract

Since the discovery of neutron stars with masses around 2 solar masses the composition of matter in the central part of these massive stars has been intensively discussed. Within this paper we will (re)investigate the question of the appearance of hyperons. To that end we will perform an extensive parameter study within relativistic mean field models. We will show that it is possible to obtain high mass neutron stars (i) with a substantial amount of hyperons, (ii) radii of 12-13 km for the canonical mass of 1.4 solar masses, and (iii) a spinodal instability at the onset of hyperons. The results depend strongly on the interaction in the hyperon-hyperon channels, on which only very little information is available from terrestrial experiments up to now.