The neutrino floor at ultra-low threshold

TL;DR

Lowering energy thresholds in dark matter detectors enables the detection of low-energy solar neutrino fluxes, including 7Be, pep, CNO, and pp, with minimal exposure, providing new insights into solar physics and dark matter searches.

Contribution

This paper demonstrates that ultra-low threshold detectors can detect various solar neutrino fluxes with minimal exposure, advancing neutrino physics and dark matter research.

Findings

Detection of 7Be neutrinos with ~10 eV threshold and 50 kg-yr exposure.

Detection of pep neutrinos with ~3 ton-yr exposure.

First potential detection of CNO neutrinos with similar exposure.

Abstract

By lowering their energy threshold direct dark matter searches can reach the neutrino floor with experimental technology now in development. The 7Be flux can be detected with $\sim 10$ eV nuclear recoil energy threshold and 50 kg-yr exposure. The pep flux can be detected with $\sim 3$ ton-yr exposure, and the first detection of the CNO flux is possible with similar exposure. The pp flux can be detected with threshold of $\sim$ eV and only $\sim$ kg-yr exposure. These can be the first pure neutral current measurements of the low-energy solar neutrino flux. Measuring this flux is important for low mass dark matter searches and for understanding the solar interior.