Speaker
Description
Faced with null results in the direct search of WIMP dark matter,
there is growing motivation to explore dark matter candidates too light to
be directly detected at current experiments. Indeed, there exists a vast
array of proposals for direct detection experiments sensitive to sub-GeV
dark matter coupled to nucleons. But can dark matter with a consistent
cosmological history populate the regions of parameter space these
proposals would be sensitive to? Furthermore, is there a maximum cross
section for sub-GeV dark matter scattering off nucleons in light of present
day constraints? In this talk, I will first estimate this maximum cross
section. I will then introduce a novel dark matter candidate which realizes
this cross section: HighlY interactive ParticlE Relics (HYPERs). The
HYPER relic abundance is set by UV freeze-in, after which a dark sector phase transition decreases the mass of the mediator which connects HYPERs to the visible
sector. This increases the HYPER's direct detection cross section, but in
such a way as to leave the HYPER's abundance unaffected. HYPERs present a
benchmark for direct detection experiments that probe light dark matter.
