Capture of Dark Matter in Neutron Stars

TL;DR

This paper presents an advanced model for Dark Matter capture in neutron stars, incorporating comprehensive physical effects to improve accuracy over previous simplified approaches, with implications for astrophysical observations.

Contribution

It introduces a fully relativistic, physically comprehensive method for calculating Dark Matter capture rates in neutron stars across a wide mass range.

Findings

Enhanced capture rate calculations accounting for all physical effects.

Applicability to various neutron star constituents and exotic particles.

Improved computational efficiency for modeling Dark Matter interactions.

Abstract

The extreme conditions in Neutron Stars make them ideal test facilities for fundamental interactions. A Neutron Star can capture Dark Matter via scattering. As a result of the scattering, Dark Matter kinetic energy is transferred to the star. An observational consequence of this can be the warming of old neutron stars to near-infrared temperatures. Different approximations or simplifications have been applied to previous analyses of the capture process. In this article, we summarise a significantly improved treatment of Dark Matter capture, which properly accounts for all relevant physical effects over a wide range of Dark Matter masses. Among them are gravitational focusing, a fully relativistic scattering treatment, Pauli blocking, neutron star opacity and multiple scattering effects. This paper cites general expressions that allow the capture rate to be computed numerically, and simplified expressions for particular types of interactions or mass regimes, which greatly increase the efficiency of computation. As a result of our method, we are able to model the scattering of Dark Matter from any neutron star constituent as well as the capture of Dark Matter in other compact objects. Our results are applied to scattering of Dark Matter from neutrons, protons, leptons and exotic baryons.