We re-examine resonant massless-neutrino conversions in a dense medium induced by flavour changing neutral current (FCNC) interactions. We show how the observed ν̅_e energy spectra from SN1987a and the supernova r-process nucleosynthesis provide constraints on supersymmetric models with R parity violation, which are much more stringent than those obtained from the laboratory. We also suggest that resonant massless-neutrino conversions may play a positive role in supernova shock reheating.

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... y, we examine the constraints on explicit R-parity-violating FCNCs in the presence of non-zero neutrino masses in the eV range, as indicated by present hot dark matter observations.