Lepton Collider as a window to Reheating (2406.11963v1)

Abstract: We propose a search strategy for MeV-scale feebly interacting massive particle (FIMP) dark matter (DM) at the $e^+e^-$ collider. We argue, detection of a mono-$\gamma$ signal plus missing energy can indicate to an MeV-scale reheating temperature of the Universe, after addressing observed DM abundance and other relevant constraints.