Explaining the XENON1T excess with Luminous Dark Matter

TL;DR

This paper proposes that the XENON1T electron recoil excess can be explained by a luminous dark matter model involving inelastic scattering and decay, with potential for future detection differentiation.

Contribution

It introduces a luminous dark matter explanation for the XENON1T excess, highlighting inelastic scattering and decay as key mechanisms, and discusses future detection strategies.

Findings

The model fits the XENON1T excess spectrum.

Inelastic scattering with ~2.75 keV mass splitting explains the data.

Future datasets can distinguish this model from other scenarios.

Abstract

We show that the excess in electron recoil events seen by the XENON1T experiment can be explained by relatively low-mass Luminous Dark Matter candidate. The dark matter scatters inelastically in the detector (or the surrounding rock), to produce a heavier dark state with a ~2.75 keV mass splitting. This heavier state then decays within the detector, producing a peak in the electron recoil spectrum which is a good fit to the observed excess. We comment on the ability of future direct detection datasets to differentiate this model from other Beyond the Standard Model scenarios, and from possible tritium backgrounds, including the use of diurnal modulation, multi-channel signals etc.,~as possible distinguishing features of this scenario.