Search for massive neutrinos in the decay π→eν

The positron spectrum from the decay π+→e+ν/sub e/ has been examined for evidence of peaks arising from an admixture in the ν/sub e/ weak eigenstate of massive neutrinos. Limits on the intensity of such peaks, together with the measured π→eν branching ratio, have been used to derive constraints on the neutrino mixing parameters over the range 4 MeV <m(ν)<135 MeV