Solar neutrino physics with low-threshold dark matter detectors

Abstract

Dark matter detectors will soon be sensitive to Solar neutrinos via two distinct channels: coherent neutrino-nucleus and neutrino-electron elastic scatterings. We establish an analysis method for extracting Solar model properties and neutrino properties from these measurements, including the possible effects of sterile neutrinos which have been hinted at by some reactor experiments and cosmological measurements. Even including sterile neutrinos, through the coherent scattering channel, a 1 ton-year exposure with a low-threshold background free Germanium detector could improve on the current measurement of the normalization of the [superscript 8]B Solar neutrino flux down to 3% or less. Combining with the neutrino-electron elastic scattering data will provide constraints on both the high- and low-energy survival probability and will improve on the uncertainty on the active-to-sterile mixing angle by a factor of 2. This sensitivity to active-to-sterile transitions is competitive and complementary to forthcoming dedicated short baseline sterile neutrino searches with nuclear decays. Finally, we show that such solar neutrino physics potentials can be reached as long as the signal-to-noise ratio is better than 0.1.