Supersymmetric radiative corrections to neutrino indices of refraction

We compute the one-loop effects on the neutrino propagation through matter induced by virtual supersymmetric particles. We show that, in the minimal version of the supersymmetric standard model, a non-degeneracy between sleptons of the second and third generations can have sizeable effects on the $\nu_\mu$--$\nu_\tau$ oscillations in matter. In particular, we discuss how this could affect the detection of the energetic neutrino fluxes arising from annihilation of supersymmetric dark matter in the center of the sun.