Probing self-interacting sterile neutrino dark matter with the diffuse supernova neutrino background

Understand

The neutrinos in the diffuse supernova neutrino background (DSNB) travel over cosmological distances and this provides them with an excellent opportunity to interact with dark relics.

• We show that a cosmologically-significant relic population of keV-mass sterile neutrinos with strong self-interactions could imprint their presence in the DSNB.
• The signatures of the self-interactions would be ``dips" in the otherwise smooth DSNB spectrum.
• Upcoming large-scale neutrino detectors, for example Hyper-Kamiokande, have a good chance of detecting the DSNB and these dips.