New Light On Dark Matter

ongoing

Collisions of dark matter (DM) particles with nuclei or with themselves can be accompanied by the prompt production of (dark) Bremsstrahlung quanta or, in matter, by the emission of electrons. The latter is called the Migdal effect, and the former adds a dissipative process to DM self-interactions. Focusing on light, sub-GeV DM candidates, we will advance two fields of central interest to the particle physics community: the direct detection of DM in the laboratory and the DM-assisted formation of structure in the Universe. The first goal is to put recent ideas of prompt photon and electron production in DM-nuclear scattering on firm and undisputable grounds. We do so by new detailed theoretical calculations for the target compounds of direct detection experiments and by devising experimental verification schemes through Standard Model analogs. The results will pioneer how we understand signal formation in DM searches and clarify the reach of state-of-the-art and future DM direct detection experiments. The second goal is to give self-interacting DM with dissipative channels an exact theory embedding. We will provide a new formulation of the Bremsstrahlung process that is exact to all orders in the colliding particle-pair interaction and spans all kinematic situations: soft- and hard-emission, quantum, and semi-classical. The results will apply broadly: from the Standard Model, to particle dark matter, to primordial black hole relics. Astrophysical implications and observational signatures will be established. The findings of these works will increase our chances of discovering DM in the laboratory and the skies and bring us closer in our quest to unravel its non-gravitational nature.