Constraints on Solar Reflected Dark Matter from a combined analysis of XENON1T and XENONnT data

TL;DR

This paper searches for low-mass dark matter particles reflected by the Sun using XENON1T and XENONnT data, setting new constraints on DM-electron scattering cross sections in previously unexplored mass ranges.

Contribution

It introduces a novel analysis method leveraging solar reflection to enhance sensitivity to low-mass dark matter in xenon detectors, providing the first constraints in certain mass ranges.

Findings

Excluded DM-electron scattering cross sections for masses 4.6 keV/c^2 to 20 keV/c^2.

Excluded DM-electron scattering cross sections for masses 0.2 MeV/c^2 to 2 MeV/c^2.

Set minimum cross section limit of 3.41×10⁻³⁹ cm² at 0.3 MeV/c^2.

Abstract

We report on a search for sub-GeV dark matter upscattered via the solar reflection mechanism in the heavy mediator scenario. Under the Standard Halo Model, keV to MeV dark matter produces nuclear recoils with energies below the detection threshold of liquid xenon time projection chambers. We enhance sensitivity to low-mass dark matter by considering dark matter-electron scattering, employing dedicated event selections to reduce the detection threshold, and exploiting the additional kinetic energy imparted to the dark matter particle by solar upscattering. Using XENON1T ionization-only and XENONnT low-energy electronic recoil datasets, we exclude previously unconstrained DM-electron scattering cross section for masses between $4.6\, \text{keV/}c^2$ and $20\, \text{keV/}c^2$, and between $0.2\, \text{MeV/}c^2$ and $2\, \text{MeV/}c^2$, reaching a minimum of $3.41\times10^{-39}\, \text{cm}^2$ for a mass of $0.3\, \text{MeV/}c^2$ at 90\% confidence level.