Enhancement of NEST Capabilities for Simulating Low-Energy Recoils in Liquid Xenon

TL;DR

This paper enhances the NEST simulation toolkit for liquid xenon, improving its modeling of low-energy nuclear and electron recoils to better support dark matter detection efforts.

Contribution

The paper introduces updated models and code improvements to NEST, making simulations of liquid xenon more accurate for low-energy recoil events.

Findings

Enhanced NEST models better match experimental data

Improved simulation of nuclear recoil yields and electric field dependence

Supports more reliable dark matter detection simulations

Abstract

The Noble Element Simulation Technique (NEST) is an exhaustive collection of models explaining both the scintillation light and ionization yields of noble elements as a function of particle type (nuclear recoil, electron recoil, alphas), electric field, and incident energy or energy loss dE/dx. It is packaged as C++ code for Geant4 that implements said models, overriding the default model which does not account for certain complexities, such as the reduction in yields for nuclear recoils (NR) compared to electron recoils (ER). We present here improvements to the existing NEST models and updates to the code which make the package even more realistic and turn it into a more full-fledged Monte Carlo simulation. All available liquid xenon data on NR and ER to date have been taken into consideration in arriving at the current models. Furthermore, NEST addresses the question of the magnitude of the light and charge yields of nuclear recoils, including their electric field dependence, thereby shedding light on the possibility of detection or exclusion of a low-mass dark matter WIMP by liquid xenon detectors.