Dark Matter Pollution in the Diffuse Supernova Neutrino Background

TL;DR

This paper investigates how low-mass dark matter annihilation could contaminate the diffuse supernova neutrino background measurements in Hyper-Kamiokande, potentially affecting parameter estimation and offering a dual detection opportunity.

Contribution

It introduces the first simulation-based analysis of dark matter annihilation as a background in DSNB measurements, highlighting its impact on parameter determination and detection challenges.

Findings

Dark matter annihilation can significantly pollute DSNB signals.

Disentangling dark matter from DSNB is difficult due to limited angular information.

Dark matter presence could enable combined DSNB and dark matter studies.

Abstract

The Hyper-Kamiokande (HyperK) experiment is expected to precisely measure the Diffuse Supernova Neutrino Background (DSNB). This requires that the backgrounds in the relevant energy range are well understood. One possible background that has not been considered thus far is the annihilation of low-mass dark matter (DM) to neutrinos. We conduct simulations of the DSNB signal and backgrounds in HyperK, and quantify the extent to which DM annihilation products can pollute the DSNB signal. We find that the presence of DM could affect the determination of the correct values of parameters of interest for DSNB physics, such as effective neutrino temperatures and star formation rates. While this opens the possibility of simultaneously characterising the DNSB and discovering dark matter via indirect detection, we argue that it would be hard to disentangle the two contributions due to the lack of angular information available at low energies.