Effects of the tensor couplings on the nucleonic direct URCA processes in neutron star matter

TL;DR

This paper investigates how tensor couplings of vector mesons influence neutrino emission and cooling in neutron star matter, revealing that these couplings can enhance neutrino emissivity and affect neutron star mass and cooling rates.

Contribution

It introduces the effect of tensor couplings of vector mesons on neutrino emissivity and neutron star properties within the relativistic Hartree-Fock framework.

Findings

Tensor couplings slightly increase maximum neutron star mass.

Tensor couplings enhance neutrino emissivity, accelerating cooling.

Tensor coupling of rho meson affects cooling rates differently at low and high densities.

Abstract

The relativistic neutrino emissivity of the nucleonic direct URCA processes in neutron star matter are investigated within the relativistic Hartree-Fock approximation. We study particularly the influences of the tensor couplings of vector mesons $\omega$ and $\rho$ on the nucleonic direct URCA processes. It is found that the inclusion of the tensor couplings of vector mesons $\omega$ and $\rho$ can slightly increase the maximum mass of neutron stars. In addition, the results indicate that the tensor couplings of vector mesons $\omega$ and $\rho$ lead to obvious enhancement of the total neutrino emissivity for the nucleonic direct URCA processes, which must accelerate the cooling rate of the non-superfluid neutron star matter. However, when considering only the tensor coupling of vector meson $\rho$, the neutrino emissivity for the nucleonic direct URCA processes slightly declines at low densities and significantly increases at high densities.That is to say that the tensor coupling of vector meson $\rho$ leads to the slow cooling rate of a low-mass neutron star and rapid cooling rate of a massive neutron star.