# Searching for Boosted Dark Matter via Dark-Strahlung

## TL;DR

This paper introduces a novel dark-strahlung detection channel for boosted dark matter, which could outperform traditional methods by providing distinctive signals in neutrino detectors like DUNE, especially in challenging background conditions.

## Contribution

The study proposes dark-strahlung as a new detection channel for boosted dark matter, demonstrating its potential to enhance sensitivity over existing elastic scattering searches.

## Key findings

- Dark-strahlung can produce 10-20% event rates in certain parameter regions.
- Dark-strahlung may outperform elastic scattering in background-limited scenarios.
- Sensitivity analysis shows dark-strahlung improves detection prospects in DUNE detectors.

## Abstract

We propose a new search channel for boosted dark matter (BDM) signals coming from the present universe, which are distinct from simple neutrino signals including those coming from the decay or pair-annihilation of dark matter. The signal process is initiated by the scattering of high-energetic BDM off either an electron or a nucleon. If the dark matter is dark-sector U(1)-charged, the scattered BDM may radiate a dark gauge boson (called "dark-strahlung") which subsequently decays to a Standard Model fermion pair. We point out that the existence of this channel may allow for the interpretation that the associated signal stems from BDM, not from the dark-matter-origin neutrinos. Although the dark-strahlung process is generally subleading compared to the lowest-order simple elastic scattering of BDM, we find that the BDM with a significant boost factor may induce an O(10-20%) event rate in the parameter regions unreachable by typical beam-produced dark-matter. We further find that the dark-strahlung channel may even outperform the leading-order channel in the search for BDM, especially when the latter is plagued by substantial background contamination. We argue that cosmogenic BDM searches readily fall in such a case, hence taking full advantage of dark-strahlung. As a practical application, experimental sensitivities expected in the leading-order and dark-strahlung channels are contrasted in dark gauge boson parameter space, under the environment of DUNE far-detectors, revealing usefulness of dark-strahlung.