By using a distributed source of atmospheric neutrinos we have carried out a long baseline neutrino experiment. The flight times of the neutrinos are up to (1/30) s. By looking for an attenuation with distance we can set mode-independent limits on the lifetime. The mean momentum for the neutrinos involved in our study is 940 MeV. Our limit is about τp/m>0.1 s at 90% confidence level.

• Received 2 June 1986

DOI:https://doi.org/10.1103/PhysRevD.35.2073