Signature of supernova neutrino flavor mixing in water erenkov detectors

We study supernova neutrino burst signals in large water erenkov detectors, examining the effects of mixing between νe and either νμ or ντ and taking account of charged current νe capture on oxygen in the detector. We show that the characteristic count rates and angular distributions from supernova neutrino-induced events can depend sensitively on the degree of neutrino flavor mixing. This sensitivity results from the different average energies expected in supernova models for νe on the one hand and νμ and ντ on the other, the steep increase in the O16(νe,e-)F16 cross section with neutrino energy, and the backward-peaked nature of the exit channel electron in this reaction. Neutrino flavor-mixing effects would be identifiable in the super Kamiokande detector for the neutrino burst of a galactic supernova.