Dark Matter Interpretation of the Super-Kamiokande Antineutrino Excess and Predictions for JUNO

TL;DR

This paper proposes that the excess of electron antineutrinos observed by Super-Kamiokande could be due to dark matter annihilating into neutrinos, with predictions for testing this hypothesis at JUNO.

Contribution

It introduces a dark matter interpretation for the neutrino excess and discusses how upcoming experiments like JUNO can test this hypothesis.

Findings

Dark matter with tens of MeV mass could explain the neutrino excess.

The proposed dark matter candidate has s-wave annihilation.

Future neutrino experiments can confirm or refute this interpretation.

Abstract

Super-Kamiokande has reported a small excess of electron antineutrino events in the 20 MeV energy range, in the search for the diffuse supernova neutrino background. We interpret this signal as a possible indication of dark matter that annihilates dominantly into neutrinos, pointing to a thermal dark matter candidate with $s$-wave annihilation and with mass in the tens of MeV range. This mass scale naturally fits into rich dark sector extensions of the Standard Model. Neutrino experiments, including JUNO, will be able to test this hypothesis in the coming years.