Reconciling Nuclear and Astrophysical Constraints

TL;DR

This paper updates the sigma model to incorporate recent astrophysical and nuclear physics constraints, resulting in improved equations of state for neutron stars that align better with observational data.

Contribution

The authors revise the non-linear sigma model to include new constraints, exploring vector meson self-interactions and delta mesons to produce more accurate neutron star equations of state.

Findings

New equations of state consistent with recent data

Better agreement with nuclear compressibility and symmetry energy

Improved predictions for neutron star masses and radii

Abstract

In view of new constraints put forth by recent observations and measurements in the realm of astrophysics and nuclear physics, we update the non-linear realization of the sigma model as to reflect such constraints. By doing this, we obtain new equations of state that may be used to describe neutron stars. Such equations of state are obtained by investigating different ways by which the vector mesons self-interact. Furthermore, we also investigate the role played by the delta mesons in the model. As a result, we are able to develop equations of state that are in better agreement with data, such as nuclear compressibility and slope of the symmetry energy at saturation, star masses, radii, and cooling profiles.