Neutral- and charged-current disintegration of deuterium by solar and supernova neutrinos

Both neutral- and charged-current neutrino-induced disintegration of deuterium are studied for energies up to 160 MeV. All relevant transition operators and final states are included. The first-forbidden transitions to $P$ states, which are often neglected, are found to be important at energies above about 40 MeV; those associated with the vector current are examined by means of an extended Siegert's theorem. Recoil corrections are included. Spectrum-averaged cross sections are calculated for solar and supernova neutrinos. Of particular significance is the resulting enhanced sensitivity of proposed heavy-water Cherenkov detectors to supernova muon and tauon neutrinos.