MSW mediated neutrino decay and the solar neutrino problem

Abstract

We investigate the solar neutrino problem assuming the simultaneous presence of MSW transitions in the Sun and neutrino decay on the way from the Sun to Earth. We do a global ${\ensuremath{\chi}}^{2}$ analysis of the data on the total rates in Cl, Ga, and SuperKamiokande (SK) experiments and the SK day-night spectrum data and determine the changes in the allowed region in the $\ensuremath{\Delta}{m}^{2}\mathrm{}\ensuremath{-}{\mathrm{tan}}^{2}\ensuremath{\theta}$ plane in the presence of decay. We also discuss the implications for unstable neutrinos in the SNO experiment.