Capture of inelastic Dark Matter in the sun

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 σn = 10−40 cm2 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−, Z0Z0, τ+τ−, tt̄ and neutrinos. Slightly weaker bounds are also available for annihilations into bb̄ and cc̄. Annihilations into lighter particles that may produce neutrinos, such as μ+μ−, 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.