S. Whitaker

Inclusive interactions of high-energy neutrinos and antineutrinos in iron

We present results on charged current inclusive neutrino and antineutrino scattering in the neutrino energy range 30–200 GeV. The results include a) total cross-sections; b)y distributions; c) structure functions; and d) scaling violations observed in the structure functions. The results, as well as their comparison with the results of electron and muon inclusive scattering, are in agreement with the expectations of the quark parton model and QCD.

Measurement of neutrino and antineutrino structure functions in hydrogen and iron

The CDHS neutrino detector has been used to measure events originating in a tank of liquid hydrogen and in the iron of the detector. Total cross-sections, differential cross-sections, and structure functions are given for hydrogen and compared with those in iron. The measurements are in agreement with the expectations of the quark parton model. No significant differences indicative of nuclear binding effects in corresponding structure functions of protons and iron are observed. This may be of special interest in the case of the sea structure functions, since large differences are expected in some models.

QCD analysis of charged-current structure functions

Abstract The structure functions F 2 ( x , Q 2 ) and xF 3 ( x , Q 2 ) measured in high-energy neutrino charged-current interactions on nuclei are compared with QCD predictions. Solutions to the moment equations of QCD are found which are in good agreement with the data and yield simple parametrisations of the structure functions. For the scale parameter Λ we find Λ = 0.5 ± 0.2 GeV. The analysis also results in values for the width of the gluon distribution as a function of Q 2 . We find 〈 x 〉 gluons = 0.16 ± 0.03 for Q 2 = 10 GeV 2 .

Measurement of the neutral to charged current cross section ratio in neutrino and antineutrino interactions

Abstract We report on the analysis of inclusive neutral current events produced in neutrino and antineutrino narrow band beams. We find for incident neutrino energies in the range 12–200 GeV and for hadron energies above 12 GeV a neutral to charged current cross-section ratio of R v = 0.293 ± 0.010 for incident neutrinos, and R v = 0.35 ± 0.03 for antineutrinos. These ratios are consistent with the Weinberg-Salam model, with sin 2 θ w = 0.24 ± 0.02.

Study of inclusive neutral current interactions of neutrinos and antineutrinos

Abstract We report on results from a study of hadron-energy distributions for ν and ν inclusive neutral current interactions. There is no significant variation of the neutral to charged current total cross-section ratios R ν and R ν with neutrino energy. The space-time structure of neutral currents is dominated by V − A , with a significant admixture of V + A . The Weinberg-Salam model is in agreement with all data if sin 2 θ w =0.24±0.02.

Comparison of moments from the valence structure function with QCD predictions

Abstract We present moments (both ordinary and Nachtmann) of the nucleon valence structure function measured in high Q 2 ν FE scattering, supplemented by data from deep inelastic eD scattering. These data seem to agree with QCD predictions for vector gluons. The QCD parameter Λ is found to be of the order 0.5 GeV.

Search for single positive muon production in neutrino interactions

Abstract A search has been made for neutrino interactions with a positive (wrong-sign) muon in the final state. All the events found can be attributed to known sources. A cut at a visible energy of 100 GeV leaves one event, giving an upper limit for μ + production relative to μ - of 1.6 × 10 −4 at the 90% confidence level. Upper limits are given for (a) charm-changing neutral currents, (b) positive heavy-lepton production, and (c) neutrino-antineutrino oscillations.

Origin of trimuon events in high-energy neutrino interactions

The properties of 76 neutrino‐initiated μ−μ−μ+ events observed in the CDHS detector in the 350 GeV and 400 GeV wide‐band beams at the CERN SPS are discussed. For neutrino energies ≳30 GeV and muon momenta ≳4.5 GeV, the average trimuon rate is (3.0±0.4) ×10−5 of the single‐muon event rate. The data are in agreement with normal charged‐current interactions with the additional production of a muon pair by both hadronic and radiative processes. No evidence is found for either heavy‐lepton or heavy‐quark cascades. Upper limits for these two possibilities are established.

Trimuon events observed in high-energy antineutrino interactions

Abstract Eight μ + μ + μ − events have been observed in the CDHS detector during the 330 GeV and 350 GeV antineutrino wide-band beam exposures at CERN. The corresponding average trimuon rate relative to the single-muon rate is (1.8 ± 0.6) × 10 −5 for visible energy ⩾ 30 GeV and muon momenta ⩾ 4.5 GeV c . Some characteristics of these antineutrino trimuon events are compared with μ − μ − μ + events produced by neutrinos.

Origin of trimuon events in high‐energy neutrino interactions

The properties of 76 neutrino‐initiated μ−μ−μ+ events observed in the CDHS detector in the 350 GeV and 400 GeV wide‐band beams at the CERN SPS are discussed. For neutrino energies ≳30 GeV and muon momenta ≳4.5 GeV, the average trimuon rate is (3.0±0.4) ×10−5 of the single‐muon event rate. The data are in agreement with normal charged‐current interactions with the additional production of a muon pair by both hadronic and radiative processes. No evidence is found for either heavy‐lepton or heavy‐quark cascades. Upper limits for these two possibilities are established.