No $\nu$ floors: Effective field theory treatment of the neutrino background in direct dark matter detection experiments

TL;DR

This paper uses non-relativistic Effective Field Theory to analyze and distinguish nuclear recoil spectra caused by dark matter and neutrinos in direct detection experiments, showing most models can be differentiated with current detector technologies.

Contribution

It provides a detailed EFT-based analysis of nuclear recoil spectra to distinguish dark matter signals from neutrino backgrounds in direct detection experiments.

Findings

Most EFT operators allow clear distinction between dark matter and neutrino-induced recoils.

Moderate-sized detectors can differentiate signals for low-mass dark matter within reasonable exposure times.

Good energy resolution enhances the ability to distinguish dark matter signals without larger or directional detectors.

Abstract

Distinguishing a dark matter interaction from an astrophysical neutrino-induced interaction will be major challenge for future direct dark matter searches. In this paper, we consider this issue within non-relativistic Effective Field Theory (EFT), which provides a well-motivated theoretical framework for determining nuclear responses to dark matter scattering events. We analyze the nuclear energy recoil spectra from the different dark matter-nucleon EFT operators, and compare to the nuclear recoil energy spectra that is predicted to be induced by astrophysical neutrino sources. We determine that for 11 of the 14 possible operators, the dark matter-induced recoil spectra can be cleanly distinguished from the corresponding neutrino-induced recoil spectra with moderate size detector technologies that are now being pursued, e.g., these operators would require 0.5 tonne years to be distinguished from the neutrino background for low mass dark matter. Our results imply that in most models detectors with good energy resolution will be able to distinguish a dark matter signal from a neutrino signal, without the need for much larger detectors that must rely on additional information from timing or direction.