# Annihilation signatures of neutron dark decay models in neutron oscillation and proton decay searches

## TL;DR

This paper explores how dark matter-neutron annihilation, predicted by models addressing the neutron lifetime anomaly, could produce observable signals in neutron oscillation and proton decay experiments like Super-Kamiokande, Hyper-Kamiokande, and DUNE.

## Contribution

It identifies specific annihilation signatures in neutron decay models that can be tested in current and future large-scale experiments.

## Key findings

- Dark matter-neutron annihilation signatures are predicted in neutron decay models.
- Observable signals include gamma and pion emissions in existing detectors.
- Potential to test dark decay models through neutron oscillation and proton decay searches.

## Abstract

We point out that two models that reconcile the neutron lifetime anomaly via dark decays of the neutron, also predict dark matter-neutron ($\bar{\chi}-n$) annihilation that may be observable in neutron-antineutron oscillation and proton decay searches at Super-Kamiokande, Hyper-Kamiokande and DUNE. We study signatures of $\bar{\chi}n\to \gamma\pi^0$ (or multi-$\pi^0$) and $\bar{\chi}n\to \phi\gamma\pi^0$ (or $\phi+$multi-$\pi^0$), where $\phi$ is an almost massless boson in one of the two models.