Observation of neutrino-like interactions without muon or electron in the Gargamelle neutrino experiment

Abstract Events induced by neutral particles and producing only hadrons, but no muon or electron, have been observed in the heavy liquid bubble chamber Gargamelle exposed to neutrino ( v ) and antineutrino ( v ) beams at CERN. A study of the various sources which could give rise to such events reveals that less than 20% could be attributed to neutrons or K L °. The events behave as expected if they arise from neutral current processes induced by neutrinos and antineutrinos. The ratio of the number of these events to the number of corresponding events with charged lepton is 0.22 ± 0.04 for v and 0.43 ± 0.12 for v .