The neutrino fog for dark matter-electron scattering experiments

TL;DR

This paper maps the neutrino fog in electron recoil dark matter experiments across various target materials, highlighting the background limits that challenge conclusive dark matter detection.

Contribution

It provides the first comprehensive mapping of the neutrino fog for electron recoil experiments with multiple target materials, defining the boundary where neutrino backgrounds dominate.

Findings

Identifies the neutrino fog boundary for silicon, germanium, xenon, and argon detectors.

Shows the neutrino background can limit dark matter discovery in certain parameter regions.

Provides a visual guide for experimental design to avoid neutrino-dominated regions.

Abstract

The search for sub-GeV dark matter via scattering on electrons has ramped up in the last few years. Like in the case of dark matter scattering on nuclei, electron-recoil-based searches also face an ultimate background in the form of neutrinos. The so-called ``neutrino fog'' refers to the range of open dark-matter parameter space where the background of neutrinos can potentially prevent a conclusive discovery claim of a dark matter signal from being made. In this study, we map the neutrino fog for a range of electron recoil experiments based on silicon, germanium, xenon and argon targets. In analogy to the nuclear recoil case, we also calculate the ''edge'' to the neutrino fog, which can be used as a visual guide to where neutrinos become an important background -- this boundary excludes some parts of the key theory milestones used to motivate these experiments.