A search for radiative neutrino decay from supernovae

If a massive neutrino species exists then it is possible that it has a radiative decay mode. Cosmological arguments require that a neutrino of mass > 100eV be unstable. Motivated by these considerations, a 3-D model of radiative neutrino decay has been developed and used to simulate the decay evolution of supernova neutrinos. A sensitive search for the decay gamma rays using extragalactic supernovae and SN1987a as neutrino sources is proceeding using the COMPTEL instrument aboard the Compton Gamma Ray Observatory. The non-observation of decay gamma rays would place more stringent mass/lifetime limits on the neutrino than current limits by about 1-6 orders of magnitude (depending on mass). Such a systematic analysis has never before been attempted. In addition, the production of the decay gamma rays over cosmological time-scales is being studied to determine its possible relationship to the diffuse gamma ray emission.