Interplay between scintillation and ionization in liquid xenon Dark Matter searches

TL;DR

This paper introduces a new method to constrain the relative scintillation efficiency in liquid xenon, which is crucial for dark matter detection, by analyzing the interplay between scintillation and ionization yields.

Contribution

It presents a novel approach combining stopping power estimates and recombination analysis to constrain L_eff from below using existing ionization data.

Findings

L_eff should not decrease at low recoil energies

The method constrains L_eff using ionization yield correlations

Implications for dark matter search exclusion limits

Abstract

We provide a new way of constraining the relative scintillation efficiency L_eff for liquid xenon. Using a simple estimate for the electronic and nuclear stopping powers together with an analysis of recombination processes we predict both the ionization and the scintillation yields. Using presently available data for the ionization yield, we can use the correlation between these two quantities to constrain L_eff from below. Moreover, we argue that more reliable data on the ionization yield would allow to verify our assumptions on the atomic cross sections and to predict the value of L_eff. We conclude that the relative scintillation efficiency should not decrease at low nuclear recoil energies, which has important consequences for the robustness of exclusion limits for low WIMP masses in liquid xenon Dark Matter searches.