CAN A CLOSURE MASS NEUTRINO HELP SOLVE THE SUPERNOVA SHOCK REHEATING PROBLEM

We point out that a nu(mu) or nu(tau) neutrino with a cosmologically significant mass (10-100 eV) and a small mixing (vacuum mixing angle theta > 10(-4)) with a light nu(e) would result in a matter-enhanced Mikheyev-Smirnov-Wolf-enstein resonant transformation between these species in a region above the neutrino sphere but below the stalled shock during the reheating phase of a Type II supernova. The neutrino heating behind the shock is due to charged-current nu(e) and nuBAR e captures. Since the nu(mu) and nu(tau) have considerably higher average energies than do the nu(e), neutrino flavor mixing would result in higher effective nu(e) energies behind the shock and a concomitant increase in the heating rate. Our numerical calculations suggest that this effect results in a 60% increase in the supernova explosion energy, possibly helping to solve the energy problem of delayed-mechanism supernova models.