Implications for dark matter particles of searches for energetic solar neutrinos

We investigate whether recent searches for energetic solar neutrinos give new constraints on candidate dark-matter particles such as photinos γ tilde and higgsinos h tilde, in view of the astrophysical and particle physics uncertainties. Previous quark model estimates of the elastic cross sections responsible for γ tilde or h tilde capture in the sun can be improved using hyperon decay data, but are thrown into doubt by recent European Muon Collaboration data on the spin-dependent proton structure function, which reduce the estimate of σ(γ tilde p) by a factor up to four. We emphasize the need to include charm and bottom quark fragmentation effects when calculating the flux of neutrinos from dark matter annihilation events, which may reduce the observable flux by a factor ≅ 2. Even the most stringent upper limits from the Frejus experiment still allow a local γ tilde or h tilde density considerably above the range of 0.20-0.43 GeV/cm3 favoured by astrophysics, and no range of msub(γ tilde) or msub(h tilde) can yet be excluded. (orig.)