Signal Yields of keV Electronic Recoils and Their Discrimination from Nuclear Recoils in Liquid Xenon

TL;DR

This study measures the response of liquid xenon to low-energy electronic recoils below 15 keV, analyzing photon yields and discrimination capabilities crucial for dark matter detection.

Contribution

It provides new measurements of photon yields and recoil discrimination at multiple drift fields, enhancing understanding of liquid xenon response at low energies.

Findings

Photon yields at low energies are consistent with previous literature.

Discrimination between electronic and nuclear recoils depends on drift field and detection efficiency.

Additional data at higher drift field improves dark matter search sensitivity.

Abstract

We report on the response of liquid xenon to low energy electronic recoils below 15 keV from beta decays of tritium at drift fields of 92 V/cm, 154 V/cm and 366 V/cm using the XENON100 detector. A data-to-simulation fitting method based on Markov Chain Monte Carlo is used to extract the photon yields and recombination fluctuations from the experimental data. The photon yields measured at the two lower fields are in agreement with those from literature; additional measurements at a higher field of 366 V/cm are presented. The electronic and nuclear recoil discrimination as well as its dependence on the drift field and photon detection efficiency are investigated at these low energies. The results provide new measurements in the energy region of interest for dark matter searches using liquid xenon.