High-Energy Neutrinos From Millicharged Dark Matter Annihilation in the Sun

Abstract: Millicharged dark matter particles can be efficiently captured by the Sun, where they annihilate into tau leptons, leading to the production of high-energy neutrinos. In contrast to the Earth, the high temperature of the Sun suppresses the fraction of millicharged particles that are bound to nuclei, allowing for potentially high annihilation rates. We recast existing constraints from the IceCube Neutrino Observatory and use this information to place new limits on the fraction of the dark matter that is millicharged. This analysis excludes previously unexplored parameter space for masses of $m_\chi \sim (5-100) \ \text{GeV}$, charges of $q_\chi \sim 10^{-3}-10^{-2}$, and fractional abundances as small as $f_{_\text{DM}} \sim 10^{-5}$.