# Solar Neutrinos as a Probe of Dark Matter-Neutrino Interactions

## TL;DR

This paper explores how interactions between dark matter and sterile neutrinos can influence solar neutrino observations, proposing a new Solar Dark MSW effect that could be detected by current experiments, offering insights into dark matter properties.

## Contribution

It introduces a realistic framework where dark matter-neutrino interactions create a new matter potential affecting solar neutrino propagation, which can be tested with solar neutrino experiments.

## Key findings

- Solar Dark MSW effect modifies high-energy neutrino fluxes.
- Parameter space where solar neutrino experiments can probe dark matter-neutrino interactions.
- Light mediators and small couplings regimes are particularly accessible.

## Abstract

Sterile neutrinos at the eV scale have long been studied in the context of anomalies in short baseline neutrino experiments. Their cosmology can be made compatible with our understanding of the early Universe provided the sterile neutrino sector enjoys a nontrivial dynamics with exotic interactions, possibly providing a link to the Dark Matter (DM) puzzle. Interactions between DM and neutrinos have also been proposed to address the long-standing "missing satellites" problem in the field of large scale structure formation. Motivated by these considerations, in this paper we discuss realistic scenarios with light steriles coupled to DM. We point out that within this framework active neutrinos acquire an effective coupling to DM that manifests itself as a new matter potential in the propagation within a medium of asymmetric DM. Assuming that at least a small fraction of asymmetric DM has been captured by the Sun, we show that a sizable region of the parameter space of these scenarios can be probed by solar neutrino experiments, especially in the regime of small couplings and light mediators where all other probes become inefficient. In the latter regime these scenarios behave as familiar $3+1$ models in all channels except for solar data, where a Solar Dark MSW effect takes place. Solar Dark MSW is characterized by modifications of the most energetic $^8$B and CNO neutrinos, whereas the other fluxes remain largely unaffected.