Solar and Atmospheric Neutrinos: Background Sources for the Direct Dark Matter Searches

TL;DR

This paper analyzes how solar and atmospheric neutrinos act as background noise in direct dark matter detection experiments, emphasizing the importance of energy thresholds and target materials for improving sensitivity.

Contribution

It provides detailed calculations of neutrino-induced background rates and establishes energy threshold requirements for various target materials to minimize neutrino interference in dark matter searches.

Findings

Solar neutrinos produce a few events per ton-year in dark matter detectors.

Energy thresholds above specific keV levels reduce neutrino background for different materials.

Atmospheric neutrinos limit the ultimate sensitivity of background-free dark matter detection.

Abstract

In experiments for direct dark matter searches, neutrinos coherently scattering off nuclei can produce similar events as Weakly Interacting Massive Particles (WIMPs). The calculated count rate for solar neutrinos in such experiments is a few events per ton-year. This count rate strongly depends on the nuclear recoil energy threshold achieved in the experiments for the WIMP search. We show that solar neutrinos can be a serious background source for direct dark matter search experiments using Ge, Ar, Xe and CaWO_4 as target materials. To reach sensitivities better than approximatly 10^-10 pb for the elastic WIMP nucleon spin-independent cross section in the zero-background limit, energy thresholds for nuclear recoils should be approximatly >2.05 keV for CaWO_4, >4.91 keV for Ge, >2.89 keV for Xe, and >8.62 keV for Ar as target material. Next-generation experiments should not only strive for a reduction of the present energy thresholds but mainly focus on an increase of the target mass. Atmospheric neutrinos limit the achievable sensitivity for the background-free direct dark matter search to approximatly >10^-12 pb.