What will we learn from the next supernova ?
Neutrinos from a future Galactic supernova will be detected by several large underground detectors. If, as expected, the mu-neutrinos and tau-neutrinos have somewhat higher energy on average than the electron neutrinos, they will dominate the neutral current response. The ways to separate the neutral and charged current signals will be discussed, and the best strategy to measure the possible time delay of the neutral current events will be outlined. Given the expected count rates, one will be able to measure in this way the tau-neutrino mass down to about 30 eV in SNO and SuperKamiokande. This represents an improvement by about 6 orders of magnitude compared to the present direct mass limits.
Neutrino signals can be also used to determine quantities of astrophysical significance. Among them are the average energies and luminosities of the different neutrino flavors. The ways with which this can be accomplished will be discussed. In particular, the (neutrino, proton) elastic scattering, which will be observable in KamLAND, will be described.
Another application is the supernova localization by the neutrino signal, prior to or independently of the electromagnetic signal. This goal can be achieved using the angular distributions of the various neutrino induced reactions. On the other hand, the triangulation, based on the arrival time of the neutrinos and widely discussed in the community, appears to be difficult and will lead only to a crude localization.