J.B.M. Pattison

Particle production in proton interactions in nuclei at 24 GeV/c

Abstract Particle production by 24 GeV/ c protons from Be, B 4 C, Al, Cu and Pb has been measured. Pion, kaon, proton and antiproton production spectra measured over a range of angles from 17 to 127 mrad and momenta from 4 to 18 GeV/ c are given in a table.

Observation of an Excess of electron-neutrino, anti-electron-neutrino 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.

Evidence for the leptonic neutral current reaction νμ+e-→νμ+e-

Abstract In the Gargamelle neutrino experiment, three unambiguous candidates for the reaction ν μ + e − → ν μ e − have been observed corresponding to a cross section for a recoil electron energy within the range 0.3 e − GeV of 0.06 × 10 −41 E ν ( GeV ) cm 2 / electron . The calculated background is 0.44 ± 0.13 events and the probability that all three candidates could be due to this background is 1%.

Evidence for the Leptonic Neutral Current Reaction anti-Muon-neutrino e- ---> anti-Muon-neutrino e-

Abstract In the Gargamelle neutrino experiment, three unambiguous candidates for the reaction ν μ + e − → ν μ e − have been observed corresponding to a cross section for a recoil electron energy within the range 0.3 e − GeV of 0.06 × 10 −41 E ν ( GeV ) cm 2 / electron . The calculated background is 0.44 ± 0.13 events and the probability that all three candidates could be due to this background is 1%.

Measurement of structure factors in inelastic neutrino scattering

Abstract Neutrino scattering cross-sections in the deep inelastic continuum have been determined and shown to exhibit the point-like behaviour, or scale invariance, previously observed in electroproduction experiments. The structure functions display the features predicted by the Pomeron exchange model for virtual W-scattering. Their magnitudes are compared with various theories.

Observation of muon-neutrino reactions producing a positron and a strange particle

Abstract In addition to one previously reported event, a second event, in which a positron is observed together with a strange particle and a negative muon, has been seen in the bubble chamber Gargamelle exposed to the CERN neutrino beam. The level of the background for this type of event is found to be very low. The data strongly indicate the existence of a new type of interaction leading to a charged lepton pair correlated with a strange particle in the final state. The interpretation of these two events in terms of production of a charmed hadron is presented.

High-energy Electronic Neutrino (

Abstract The total cross-sections for v e ( v e ) -nucleon scattering have been measured. A test has been made of the muon number conservation law. A limit of 2.4 GeV is found the mass of the “Georgi-Glashow type” heavy lepton

\nu_e

Abstract Using a propane bubble chamber the average cross-section for single pion production by neutrinos on free protons has been determined to be (1.13 ± 0.28) × 10 −38 cm 2 for neutrinos of energy between 1 and 4 GeV. The invariant mass distribution of the ( π p) system indicates that N ∗ (1236) production is the dominant process. Angular distributions of the pion in the ( π p) rest frame are also presented. The results of the experiment are compared with theoretical predictions.

) and Anti-neutrino (

Abstract The 90% confidence limit for the coupling constant for ν e + e − →e − + ν e is found to be G diagonal G Fermi . Upper limits for two possible neutral current processes are found to be : ( ν μ + p→ ν μ + p)/( ν μ + n→ μ − + p) = 0.12 ± 0.06 and ( ν μ + p→ ν μ + π + + n)/( ν μ + p→ μ − + π + + p) = 0.08 ± 0.04.

\bar{\nu}_e

Abstract A sample of 357 events fitting the reaction ν + p → μ − + p + π + on free proton is obtained from the Gargamelle neutrino propane experiment at the CERN-PS. The average value of the cross section above 1 GeV is found to be (0.60 ± 0.07) 10 −38 cm 2 . The reaction is dominated by the production of the Δ ++ (1232) resonance. Results on the Δ ++ spin density matrix are given.