# Strong New Limits on Light Dark Matter from Neutrino Experiments

## TL;DR

This paper demonstrates how neutrino experiments can set new limits on sub-GeV light dark matter by analyzing cosmic-ray interactions and relativistic dark matter flux, expanding the exclusion parameter space.

## Contribution

It introduces novel analysis methods and data sources to improve constraints on light dark matter from neutrino experiments, surpassing previous limits.

## Key findings

- Neutrino experiments exclude larger parameter space for sub-GeV dark matter.
- Cosmic-ray elastic scattering can produce detectable relativistic dark matter flux.
- Strategies to further enhance sensitivity to light dark matter are proposed.

## Abstract

The non-detection of GeV-scale WIMPs has led to increased interest in more general candidates, including sub-GeV dark matter. Direct detection experiments, despite their high sensitivity to WIMPs, are largely blind to sub-GeV dark matter. Recent work has shown that cosmic-ray elastic scattering with sub-GeV dark matter would both alter the observed cosmic ray spectra and produce a flux of relativistic dark matter, which would be detectable with traditional dark matter experiments as well as larger, higher-threshold detectors for neutrinos. Using data, detectors, and analysis techniques not previously considered, we substantially increase the regions of parameter space excluded by neutrino experiments for both dark matter-nucleon and dark matter-electron elastic scattering. We also show how to further improve sensitivity to light dark matter.