Capture of Inelastic Dark Matter in the Sun

TL;DR

This paper investigates how inelastic dark matter can be captured by the Sun and shows that current neutrino flux bounds strongly constrain certain dark matter annihilation channels, especially those producing high-energy neutrinos.

Contribution

It demonstrates that inelastic dark matter capture in the Sun leads to significant constraints on annihilation channels based on neutrino flux bounds, linking astrophysical observations to dark matter properties.

Findings

Current bounds exclude high-energy neutrino-producing annihilations.

Light particle channels like muons and pions are not constrained.

Results are consistent with models explaining PAMELA data.

Abstract

We consider the capture of dark matter in the Sun by inelastic scattering against nuclei as in the inelastic dark matter scenario. We show that, assuming a WIMP-nucleon cross-section of \sigma_n = 10^{-40}\cm^2 the resulting capture rate and density are sufficiently high so that current bounds on the muon neutrino flux from the Sun rule out any appreciable annihilation branching ratio of WIMPs into W^+W^-, Z^0Z^0, \tau^+\tau^-, t\bar{t} and neutrinos. Slightly weaker bounds are also available for annihilations into b\bar{b} and c\bar{c}. Annihilations into lighter particles that may produce neutrinos, such as \mu^+\mu^-, pions and kaons are unconstrained since those stop in the Sun before decaying. Interestingly enough, this is consistent with some recent proposals motivated by the PAMELA results for the annihilation of WIMPs into light bosons which subsequently decay predominantly into light leptons and pions.