Detecting Boosted Dark Matter from the Sun with Large Volume Neutrino Detectors

TL;DR

This paper proposes a novel detection method for boosted dark matter originating from the Sun, utilizing large volume neutrino detectors like Super-Kamiokande, which can identify proton tracks pointing towards the Sun.

Contribution

It introduces new models of semi-annihilating and multi-component dark matter that produce boosted particles, and demonstrates their detectability with existing neutrino detectors.

Findings

Boosted dark matter can produce detectable proton recoil signals.

Cherenkov detectors like SK and HK can achieve sensitivity comparable to direct detection.

Proposed method is consistent with current experimental constraints.

Abstract

We study novel scenarios where thermal dark matter (DM) can be efficiently captured in the Sun and annihilate into boosted dark matter. In models with semi-annihilating DM, where DM has a non-minimal stabilization symmetry, or in models with a multi-component DM sector, annihilations of DM can give rise to stable dark sector particles with moderate Lorentz boosts. We investigate both of these possibilities, presenting concrete models as proofs of concept. Both scenarios can yield viable thermal relic DM with masses O(1)-O(100) GeV. Taking advantage of the energetic proton recoils that arise when the boosted DM scatters off matter, we propose a detection strategy which uses large volume terrestrial detectors, such as those designed to detect neutrinos or proton decays. In particular, we propose a search for proton tracks pointing towards the Sun. We focus on signals at Cherenkov-radiation-based detectors such as Super-Kamiokande (SK) and its upgrade Hyper-Kamiokande (HK). We find that with spin-dependent scattering as the dominant DM-nucleus interaction at low energies, boosted DM can leave detectable signals at SK or HK, with sensitivity comparable to DM direct detection experiments while being consistent with current constraints. Our study provides a new search path for DM sectors with non-minimal structure.