A Comprehensive Study of Low-Energy Response for Xenon-Based Dark Matter Experiments

TL;DR

This paper presents a detailed model of low-energy recoil responses in xenon-based dark matter detectors, highlighting plasma effects and recoil type differences, aligning well with experimental data.

Contribution

It introduces a plasma-based recombination model that explains charge and light yields for both electronic and nuclear recoils in xenon detectors.

Findings

Volume recombination constrained by plasma effects.

Different plasma times for electronic and nuclear recoils.

Model agrees with experimental data.

Abstract

We report a comprehensive study of the energy response to low-energy recoils in dual-phase xenon-based dark matter experiments. A recombination model is developed to explain the recombination probability as a function of recoil energy at zero field and non-zero field. The role of e-ion recombination is discussed for both parent recombination and volume recombination. We find that the volume recombination under non-zero field is constrained by a plasma effect, which is caused by a high density of charge carriers along the ionization track forming a plasma-like cloud of charge that shields the interior from the influence of the external electric field. Subsequently, the plasma time that determines the volume recombination probability at non-zero field is demonstrated to be different between electronic recoils and nuclear recoils due to the difference of ionization density between two processes. We show a weak field-dependence of the plasma time for nuclear recoils and a stronger field-dependence of the plasma time for electronic recoils. As a result, the time-dependent recombination is implemented in the determination of charge and light yield with a generic model. Our model agrees well with the available experimental data from xenon-based dark matter experiments.