Atmospheric Dark Matter and Xenon1T Excess

TL;DR

This paper proposes atmospheric dark matter produced by cosmic ray interactions as an explanation for the Xenon1T electron recoil excess, fitting the data with a specific scattering cross section and suggesting future experimental tests.

Contribution

It introduces a novel atmospheric dark matter model from cosmic ray collisions that explains the Xenon1T anomaly and predicts detectable signals in rare meson decays.

Findings

Light ADM can fit the Xenon1T excess spectrum.

Predicted scattering cross section evades current constraints.

Future searches in rare meson decays can test the model.

Abstract

Very recently, the Xenon1T collaboration has reported an intriguing electron recoil excess, which may imply for light dark matter. In order to interpret this anomaly, we propose the atmospheric dark matter (ADM) from the inelastic collision of cosmic rays (CRs) with the atmosphere. Due to the boost effect of high energy CRs, we show that the light ADM can be fast-moving and successfully fit the observed electron recoil spectrum through the ADM-electron scattering process. Meanwhile, our ADM predicts the scattering cross section $\sigma_e \sim {\cal O}(10^{-38}- 10^{-39}$) cm$^{2}$, and thus can evade other direct detection constraints. The search for light meson rare decays, such as $\eta \to \pi + \slashed E_T$, would provide a complementary probe of our ADM in the future.