Constraints on Spin-Dependent Dark Matter Scattering with Long-Lived Mediators from TeV Observations of the Sun with HAWC

TL;DR

This paper uses three years of HAWC gamma-ray data to set new, stringent limits on spin-dependent dark matter interactions with the Sun, especially for masses above 1 TeV, surpassing direct detection bounds.

Contribution

It provides novel constraints on TeV-scale dark matter spin-dependent scattering cross sections using gamma-ray observations of the Sun, focusing on long-lived mediators and extending the mass range beyond previous limits.

Findings

No significant gamma-ray emission detected from the Sun.

Constraints on dark matter-proton cross section as low as 10^{-45} cm^2 for 1 TeV mass.

Constraints surpass current direct detection experiments by several orders of magnitude.

Abstract

We analyze the Sun as a source for the indirect detection of dark matter through a search for gamma rays from the solar disk. Capture of dark matter by elastic interactions with the solar nuclei followed by annihilation to long-lived mediators can produce a detectable gamma-ray flux. We search three years of data from the High Altitude Water Cherenkov Observatory and find no statistically significant detection of TeV gamma-ray emission from the Sun. Using this, we constrain the spin-dependent elastic scattering cross section of dark matter with protons for dark matter masses above 1 TeV, assuming an unstable mediator with a favorable lifetime. The results complement constraints obtained from Fermi-LAT observations of the Sun and together cover WIMP masses between 4 GeV and $10^6$ GeV. The cross section constraints for mediator decays to gamma rays can be as strong as $\sim10^{-45}$ cm$^{-2}$, which is more than four orders of magnitude stronger than current direct-detection experiments for 1 TeV dark matter mass. The cross-section constraints at higher masses are even better, nearly 7 orders of magnitude better than the current direct-detection constraints for 100 TeV dark matter mass. This demonstration of sensitivity encourages detailed development of theoretical models in light of these powerful new constraints.