The Sun Can Strongly Constrain Spin-Dependent Dark Matter Nucleon Scattering Below the Evaporation Limit

TL;DR

This paper demonstrates that solar observations can significantly constrain spin-dependent dark matter interactions at low masses, surpassing terrestrial experiments and accounting for evaporation effects.

Contribution

It introduces a detailed analysis of how dark matter evaporation influences solar constraints on spin-dependent scattering, extending limits below previous fixed evaporation thresholds.

Findings

Solar observations outperform terrestrial constraints for 2-4 GeV DM

Constraints exceed terrestrial limits by 1-5 orders of magnitude

Provides leading constraints below 0.2 GeV where direct detection is limited

Abstract

The Sun is a promising target for dark matter (DM) searches due to its ability to accumulate DM particles via scattering and catalyze their self-annihilation. However, at low DM masses, DM particles can also "evaporate" due to subsequent collisions with the hot thermal plasma of the Sun. While several modeling studies have calculated the competitive dynamics of DM evaporation and annihilation, observational studies have typically assumed a fixed 4 GeV "evaporation limit", below which DM evaporates before it can annihilate. In this paper, we consider the competitive effects of DM evaporation and annihilation on spin-dependent DM nucleon cross-section limits, finding that Solar observations can continue to exceed terrestrial constraints by between 1-5 orders of magnitude for DM masses between 2-4 GeV, and can even provide world leading constraints below 0.2 GeV where direct detection is limited.