  Dark photons, hypothetical feebly interacting massive vector bosons, appear
in many extensions of the Standard Model. This study investigates their
production and subsequent decay during supernova explosions. We demonstrate
that the decay of dark photons, with masses ranging from 200 to 400 MeV, can
lead to the emission of neutrinos with energies surpassing those emitted by
supernovae. These neutrinos therefore serve as a distinct signal of new
physics, allowing for the exploration of previously uncharted regions of the
dark photon parameter space and complementing both accelerator-based searches
and other astrophysical constraints. The signal is largely unaffected by the
specifics of the supernova's temperature and density radial profiles outside
the SN core, rendering the prediction both robust and model-independent. Our
results indicate that searching for high-energy neutrinos accompanying
supernova explosions provides a novel approach to probe physics beyond the
Standard Model, including dark photons, heavy neutral leptons, and other feebly
interacting particles with masses in the hundreds of MeV range.
