On the Minimum Dark Matter Mass Testable by Neutrinos from the Sun

TL;DR

This paper investigates the lower mass limit of dark matter particles detectable via solar neutrinos, highlighting the role of evaporation effects that limit constraints on very light dark matter.

Contribution

It identifies the minimum dark matter mass detectable through solar neutrino signals and provides fitting functions for GeV-scale dark matter processes in the Sun.

Findings

Dark matter masses below ~4 GeV cannot be constrained by solar neutrinos due to evaporation effects.

The paper provides analytical fitting functions for dark matter capture and evaporation processes.

It establishes the mass threshold where neutrino-based detection becomes ineffective.

Abstract

We discuss a limitation on extracting bounds on the scattering cross section of dark matter with nucleons, using neutrinos from the Sun. If the dark matter particle is sufficiently light (less than about 4 GeV), the effect of evaporation is not negligible and the capture process goes in equilibrium with the evaporation. In this regime, the flux of solar neutrinos of dark matter origin becomes independent of the scattering cross section and therefore no constraint can be placed on it. We find the minimum values of dark matter masses for which the scattering cross section on nucleons can be probed using neutrinos from the Sun. We also provide simple and accurate fitting functions for all the relevant processes of GeV-scale dark matter in the Sun.