Searches for dark matter decay with ultra-high-energy neutrinos endure backgrounds

TL;DR

Next-generation UHE neutrino telescopes can effectively search for heavy dark matter decay into neutrinos by analyzing event distributions, even with unknown backgrounds, promising significant discovery potential.

Contribution

This paper demonstrates that angular and energy distribution analysis enhances dark matter decay searches in future UHE neutrino telescopes despite unknown backgrounds.

Findings

Effective background mitigation using event distributions.

Potential to measure dark matter mass and lifetime.

Strong limits on dark matter lifetime achievable.

Abstract

Next-generation ultra-high-energy (UHE) neutrino telescopes, presently under planning, will have the potential to probe the decay of heavy dark matter (DM) into UHE neutrinos, with energies in excess of $10^7$~GeV. Yet, this potential may be deteriorated by the presence of an unknown background of UHE neutrinos, cosmogenic or from astrophysical sources, not of DM origin and seemingly large enough to obscure the DM signature. We show that leveraging the angular and energy distributions of detected events safeguards future searches for DM decay against such backgrounds. We focus on the radio-detection of UHE neutrinos in the planned IceCube-Gen2 neutrino telescope, which we model in state-of-the-art detail. We report promising prospects for the discovery potential of DM decay into UHE neutrinos, the measurement of DM mass and lifetime, and limits on the DM lifetime, despite the presence of a large background, without prior knowledge of its size and shape.