Detailed neutrino spectra from cold dark-matter annihilations in the sun

Abstract

Cold dark-matter particles captured by the Sun can annihilate and may produce an observable flux of high-energy neutrinos. We discuss the effects of the solar medium upon the neutrino flux. Muons, pions, and kaons lose their energy to the medium before undergoing a weak decay, so that the flux is dominated by prompt neutrinos from τ, c, b, or t decays. We calculate the differential fluxes of neutrinos from annihilations via τ τ , c c , b b , and t t final states using a successful model for final states in e + e − collisions augmented by our solar medium considerations. Fragmentation and finite-mass effects are important for b and c decays. For sufficiently energetic fermions, stopping and absorption are important. We give the results of our calculations in a form useful for estimating event rates in terrestrial experiments. Finally, we apply our results to the case of a superstring dark-matter candidate.