Singularities in the gravitational capture of dark matter through longrange interactions
Abstract
We reexamine the gravitational capture of dark matter (DM) through longrange interactions. We demonstrate that neglecting the thermal motion of target particles, which is often a good approximation for shortrange capture, results in parametrically inaccurate results for longrange capture. When the particle mediating the scattering process has a mass that is small in comparison to the momentum transfer in scattering events, correctly incorporating the thermal motion of target particles results in a quadratic, rather than logarithmic, sensitivity to the mediator mass, which substantially enhances the capture rate. We quantitatively assess the impact of this finite temperature effect on the captured DM population in the Sun as a function of mediator mass. We find that capture of DM through light dark photons, as in e.g. mirror DM, can be powerfully enhanced, with selfcapture attaining a geometric limit over much of parameter space. For visiblydecaying dark photons, thermal corrections are not large in the Sun, but may be important in understanding longrange DM capture in more massive bodies such as Population III stars. We additionally provide the first calculation of the longrange DM selfevaporation rate.
 Publication:

Journal of Cosmology and Astroparticle Physics
 Pub Date:
 January 2022
 DOI:
 10.1088/14757516/2022/01/016
 arXiv:
 arXiv:2110.02234
 Bibcode:
 2022JCAP...01..016G
 Keywords:

 dark matter theory;
 first stars;
 solar physics;
 High Energy Physics  Phenomenology
 EPrint:
 v2: version accepted for publication in JCAP