Superheavy WIMP dark matter from incomplete thermalization

Abstract

Abstract Although it is usually thought that a class of weakly interacting massive particle (WIMP) dark matters (DMs), which have the vector coupling with the Z boson, is denied by null results of the direct DM searches, such WIMP DMs are still viable if they are superheavy with the mass of mDM & 10 9 GeV. In the future, the superheavy WIMP DMs can be searched up to mDM ≃ 1012 GeV, which corresponds to the so-called neutrino floor limit. We show that the observed abundance of ΩDMh 2 ≃ 0.1 for a superheavyWIMP DM can be reproduced by a suitable reheating temperature of TR ≃ mDM/29 after inflation, if the direct inflaton decay into DM is negligible or kinematically forbidden.