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

TL;DR

This paper explores how self-interacting sterile neutrinos could leave detectable signatures in the diffuse supernova neutrino background, providing a new way to probe dark matter properties with future neutrino detectors.

Contribution

It proposes that self-interacting sterile neutrinos can produce observable dips in the DSNB spectrum, offering a novel method to constrain or detect such dark matter candidates.

Findings

Self-interacting sterile neutrinos can cause spectral dips in the DSNB.

Upcoming detectors like Hyper-Kamiokande can potentially observe these dips.

Non-detection of dips constrains sterile neutrino properties.

Abstract

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. If no dips are detected, this method serves as an independent constraint on the sterile neutrino self-interaction strength and mixing with active neutrinos. We show that relic sterile neutrino parameters that evade X-ray and structure bounds may nevertheless be testable by future detectors like TRISTAN, but may also produce dips in the DSNB which could be detectable. Such a detection would suggest the existence of a cosmologically-significant, strongly self-interacting sterile neutrino background, likely embedded in a richer dark sector.