Microscopic nuclear equation of state with three-body forces and neutron star structure

TL;DR

This paper computes neutron star properties using a microscopic nuclear equation of state with three-body forces, predicting maximum masses and cooling processes consistent with observations, and compares different nuclear force models.

Contribution

It introduces a microscopic EOS incorporating three-body forces for neutron star modeling, providing new predictions for maximum mass and cooling thresholds.

Findings

Maximum neutron star mass of 1.8-1.94 solar masses.

Onset of direct Urca processes at specific densities.

Variation in cooling behavior depending on nuclear force model.

Abstract

We calculate static properties of non-rotating neutron stars (NS's) using a microscopic equation of state (EOS) for asymmetric nuclear matter, derived from the Brueckner-Bethe-Goldstone many-body theory with explicit three-body forces. We use the Argonne AV14 and the Paris two-body nuclear force, implemented by the Urbana model for the three-body force. We obtain a maximum mass configuration with $ M_{max} = 1.8 M_{\sun}$ ($M_{max} = 1.94 M_{\sun}$) when the AV14 (Paris) interaction is used. They are both consistent with the observed range of NS masses. The onset of direct Urca processes occurs at densities $n \geq 0.65~fm^{-3}$ for the AV14 potential and $n \geq 0.54~fm^{-3}$ for the Paris potential. Therefore, NS's with masses above $M^{Urca} = 1.4 M_{\sun}$ for the AV14 and $M^{Urca} = 1.24 M_{\sun}$ for the Paris potential can undergo very rapid cooling, depending on the strength of superfluidity in the interior of the NS. The comparison with other microscopic models for the EOS shows noticeable differences.