Nuclear Recoil Calibration at Sub-keV Energies in LUX and Its Impact on Dark Matter Search Sensitivity

TL;DR

This paper presents a calibration of liquid xenon detectors at sub-keV energies, improving the understanding of their response to low-mass dark matter interactions and enhancing future detection sensitivity.

Contribution

It provides the first direct measurements of light and charge yields at energies as low as 0.45 keV and 0.27 keV in LXe detectors, approaching the physical detection limit.

Findings

Light and charge yields measured down to 0.45 keV and 0.27 keV.

Results approach the single quantum production limit.

Implications for low-mass dark matter detection sensitivity.

Abstract

Dual-phase xenon time projection chamber (TPC) detectors offer heightened sensitivities for dark matter detection across a spectrum of particle masses. To broaden their capability to low-mass dark matter interactions, we investigated the light and charge responses of liquid xenon (LXe) to sub-keV nuclear recoils. Using neutron events from a pulsed Adelphi Deuterium-Deuterium neutron generator, an in situ calibration was conducted on the LUX detector. We demonstrate direct measurements of light and charge yields down to 0.45 keV and 0.27 keV, respectively, both approaching single quanta production, the physical limit of LXe detectors. These results hold significant implications for the future of dual-phase xenon TPCs in detecting low-mass dark matter via nuclear recoils.