Regenerating WIMPs in the light of direct and indirect detection

TL;DR

This paper explores how the freeze-in mechanism can explain dark matter relic density and examines the constraints from gamma-ray and direct detection experiments, focusing on neutralino dark matter in the MSSM.

Contribution

It demonstrates that certain dark matter candidates with correct relic density via freeze-in can still be excluded by experimental constraints, with a detailed analysis of neutralinos in the MSSM.

Findings

Freeze-in can produce correct relic density for some candidates.

Experimental constraints can exclude candidates despite freeze-in.

Analysis focused on neutralino dark matter in the MSSM.

Abstract

There are several ways to explain the dark matter relic density other than by the ordinary freeze-out scenario. For example, the freeze-in mechanism may constitute an alternative for generating the correct relic density for dark matter candidates whose predicted freeze-out abundance is too low due to a large total annihilation cross section. Here we show that although such a mechanism could explain why a dark matter candidate has the correct relic density, some candidates may still be ruled out because they would lead to a large gamma ray flux in dwarf spheroidal galaxies or a large elastic scattering rate in direct detection experiments. To investigate this scenario we examine neutralino dark matter in the MSSM. However our conclusions can be generalised to other types of annihilating DM candidates with a low relic density in the freeze-out scenario but which have their relic densities generated by some other mechanism.