Supernova cooling from neutrino-devouring dark matter

Supernova cooling provides a powerful probe of physics beyond the Standard Model (SM), in particular for new, light states interacting feebly with SM particles. In this Letter, we investigate for the first time the production of fermionic dark matter (DM) via the neutrino-devouring process inside a core-collapse supernova, which contributes to the excessive cooling of the supernova. By incorporating state-of-the-art supernova simulation data and the full time evolution information, we derive stringent and robust limits on DM interactions, which can improve upon direct detection limits by several orders of magnitude. We exclude the cross sections down to 10^-51 - 10^-58 cm² in the keV-MeV mass range for DM-electron scattering, and 10^-49 - 10^-56 cm² in the 0.1-100 MeV mass range for DM-nucleon scattering, supplemented by complementary constraints from cosmology, astrophysics, colliders and direct detection experiments in the larger cross section regime. We also close almost the entire window in which fermionic DM constitutes O(1) fraction of DM due to its coupling to electrons in the keV-MeV mass range.