Solar neutrinos at keV energies: thermal flux

TL;DR

This paper discusses the thermal flux of solar neutrinos in the keV energy range, highlighting its potential to inform solar physics and impact dark matter searches, yet noting its absence in common analyses.

Contribution

It identifies and characterizes the thermal neutrino flux at keV energies from the Sun, emphasizing its significance for astrophysics and dark matter experiments.

Findings

Thermal neutrino flux dominates in the keV range.

Such flux is absent in typical all-sources neutrino spectra.

Implications for solar physics and dark matter detection.

Abstract

The neutrino flux at Earth is dominated in the keV energy range by the neutrinos produced in the Sun through thermal processes, namely photo production, bremsstrahlung, plasmon decay, and emission in free-bound and bound-bound transitions of partially ionized elements heavier than hydrogen and helium. Such a component of the neutrino flux is conspicuously absent from popular analyses of the all-sources spectrum at Earth, whereas if detected it could be a source of information about solar physics. Moreover, it would be the relevant background for keV-mass sterile neutrino dark matter direct searches.