Illuminating the dark: mono-γ signals at NA62

Dipole interactions between dark sector states or between a Standard Model particle and a dark state can efficiently be searched for via high-intensity fixed-target facilities. We propose to look for the associated mono-γ signature at the NA62 experiment running in beam dump mode. Focusing on models of dipole inelastic Dark Matter and active-sterile neutrino dipole interactions, we compute the corresponding expected sensitivities finding promising prospects for discovery already with ~ 1017 proton-on-target, corresponding to the present accumulated dataset.