Constraining Asymmetric DM Properties by Black Hole Formation in Neutron Stars and Population III Stars

TL;DR

This paper investigates how neutron stars and Population III stars can be used to constrain properties of bosonic asymmetric dark matter, especially in high-density environments and for low-mass particles, by analyzing capture and evaporation effects.

Contribution

It introduces new methods to constrain ADM properties using neutron stars and Population III stars, including closed-form approximations for DM evaporation rates in various states.

Findings

Neutron stars in high DM density environments are significantly affected by capture and evaporation.

Population III stars are effective probes for low-mass ADM, especially below 10^{-15} GeV.

Derived analytical formulas for DM evaporation from polytropic objects and BEC states.

Abstract

In this work we explore the potential for Neutron Stars (NSs) at the Galactic center and Population~III stars to constrain bosonic Asymmetric Dark Matter (ADM). We demonstrate that for NSs in an environment of sufficiently high DM density ($\rho_\chi\gtrsim10^{9}\text{GeV/cm}^3$), the effects of both multiscatter capture and DM evaporation cannot be neglected. Conversely, for Pop~III stars, we find they are excellent at probing low-mass ADM. For instance, the most easily observable Population III stars could be highly effective at constraining high-$\sigma$ low-$m_\chi$ DM, maintaining efficacy below $m_\chi=10^{-15}\text{GeV}$ (assuming a Bose Einstein Condensate(BEC) forms) thanks to their far lower value of $m_\chi$ at which capture saturates to the geometric limit. Finally, we derive closed-form approximations for the evaporation rate of DM from arbitrary polytropic objects and from DM particles in a BEC state.