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

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 (${\rho }_{\chi }\gtrsim 10^9{\text{GeV/cm}}^3$), 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.