New Experimental Limit on the Muon-neutrino Lifetime

We find no evidence for ..nu../sub ..mu../ or anti ..nu../sub ..mu../ decays for any two-body decay mode in which a photon is emitted. The 90% confidence level limit which we set is tau ..nu../sub ..mu../M..nu../sub ..mu../ > 0.11, where M..nu../sub ..mu../ is the mass of the muon neutrino in eV and tau ..nu../sub ..mu../ is the muon neutrino lifetime in seconds.