E. Fiorini

Observation of Neutrino Like Interactions Without Muon Or Electron in the Gargamelle Neutrino Experiment

Abstract Events induced by neutral particles and producing hadrons, but no muon or electron, have been observed in the CERN neutrino experiment. These events behave as expected if they arise from neutral current induced processes. The rates relative to the corresponding charged current processes are evaluated.

Search for elastic muon-neutrino electron scattering

Abstract One possible event of the process ν − μ + e − → v − μ + e − has been observed. The various background processes are discussed and the event interpreted in terms of the Weinberg theory. The 90% confidence limits on the Weinberg parameter are 0.1 2 θ W

Measurement of the neutrino--nucleon and antineutrino--nucleon total cross sections

Abstract The v and v nucleon total cross-sections have been determined as a function of energy using a sample of 2500 v and 950 v event. The results are compared with predictions of scaling and charge symmetry hypotheses.

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

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 KL°. 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.

Observation of an excess of νe, νe events in a beam dump experiment at 400 GeV

Abstract A beam dump experiment has been performed at CERN in Gargamelle using the neutrino facility to look for penetrating particles produced either directly in the beam interaction or by prompt decay of new particles. A total of 32 interactions with a visible energy greater than 10 GeV has been found, classified, aftercorrections, into 18 charged current ν μ or ν μ , 5.1 neutral current and 8.9 ν e or ν e charged current events. An excess of ν e events remains after all subtractions from any established sources. Results are presented in terms of the product of the cross section and the leptonic decay branching ratio of the possible source.

Observation of "elastic" hyperon production by antineutrinos

Abstract The production of Λ and Σ0 hyperons by antineutrinos has been observed. These events have been used to estimate the production cross-section on protons. The result is compared with the predictions of the Cabibbo theory for the process ν p → μ + Λ .

Limits on the mass and lifetime of long-lived heavy neutral leptons

Abstract A beam dump experiment was performed in the CERN Gargamelle neutrino facility in order to look for new heavy penetrating neutral particles. Limits are determined for the mass and lifetimes of such particles, and also the cross section for their production.

Experiments on Lepton and Baryon Stability and Oscillation Phenomena

The various experiments on lepton number conservation and on nucleon stability currently being done or prepared are reviewed, and their relative merits compared and discussed. The first part of the paper is devoted to the measurement of the neutrino mass and to the present limits on the conservation of the total lepton number and of the various lepton flavours. The existing results and future projects on the strictly connected problems of neutrino oscillations at nuclear reactors, pion factories and high energy accelerators will be also discussed, together with oscillations of solar and atmospheric neutrinos. The second part of the paper concerns the few results and the m any planned detectors on nucleon decay with particular emphasis on the problems of background radioactivity and of the variety of experimental approaches. Oscillation experiments on neutron—antineutron oscillations at nuclear reactors are also considered.

Weak interactions and symmetries

Abstract A few problems and recent results in weak interaction physics which have some implication in nuclear physics will be reviewed. After a brief discussion on parity non conservation in nuclei, the present experimental situation and the future plans for investigating lepton and baryon non conservation will be considered. I will discuss in particular experiments on double beta decay both to ground and to excited levels, also in view of a possible non-zero neutrino mass. The paper will be concluded by a review of the present and planned experiments on nucleon decay and on neutron-antineutron oscillations.

Strange particle production by neutral currents in the "Gargamelle" neutrino and antineutrino experiments

Abstract The production rates of strange particles in pairs via neutral currents in ν and ν reactions have been measured in the “Garmelle” freon experiment. An upper limit for the fraction of the nucleon momentum carried is also given.