Multicomponent multiscatter capture of dark matter
Cosmin Ilie, Caleb Levy
Abstract
In recent years, the usefulness of astrophysical objects as dark matter (DM) probes has become more and more evident, especially in view of null results from direct-detection and particle-production experiments. The potentially observable signatures of DM gravitationally trapped inside a star, or another compact astrophysical object, have been used to forecast stringent constraints on the nucleon--dark matter interaction cross section. Currently, the probes of interest are at high redshifts, Population III (Pop III) stars that form in isolation or in small numbers, in very dense DM minihalos at $z\ensuremath{\sim}15--40$, and, in our own Milky Way, neutron stars, white dwarfs, brown dwarfs, exoplanets, etc. None of these objects are truly single component and, as such, capture rates calculated with the common assumption made in the literature of single-component capture, i.e., capture of DM by multiple scatterings with one single type of nucleus inside the object, are not accurate. In this paper, we present an extension of this formalism to multicomponent objects and apply it to Pop III stars, thereby investigating the role of He in the capture rates of Pop III stars. As expected, we find that the inclusion of the heavier He nuclei leads to an enhancement of the overall capture rates, further improving the potential of Pop III stars as dark matter probes.