THE SIGNAL FROM A GALACTIC SUPERNOVA - MEASURING THE TAU-NEUTRINO MASS

We have developed a comprehensive Monte Carlo analysis in order to simulate the neutrino signal from a galactic supernova in a large water Cerenkov detector. This allows us to demonstrate that, by exploiting the various features of the signal in a way which is largely independent of the supernova model, assuming only that the late-time behaviour of the signal is flavor independent, a sensitivity to a tau-neutrino mass down to the cosmologically interesting range of almost-equal-to 25 eV for a medium luminosity burst is possible. This is the case even though the tau signal involves almost-equal-to 50 out of almost-equal-to 10000 total events in a detector of the size of that proposed for "Super Kamiokande". In addition, our results allow us to elucidate several aspects of a supernova neutrino signal in water detectors which had not been previously explored, including new results on the observability of the neutronization burst.