J. Wotschack

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.

A detector for high-energy neutrino interactions

Abstract We describe the design, construction and performance of a large mass detector used at CERN to study high-energy neutrino interactions in iron. This detector combines magnetic spectrometry and hadron calorimetry techniques.

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 .

Performance of a magnetized total absorption calorimeter between 15 GeV and 140 GeV

Abstract We have calibrated a magnetized iron-scintillator sandwhich calorimeter in a hadron beam, finding an energy resolution equal to 16% fwhm at 140 GeV with 5 cm sampling. The hadron energy resolution (fwhm/mean) improves as E − 1 2 between 15 and 140 GeV. No effect due to the magnetic field was observed. Longitudinal and lateral shower containment were also investigated.

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.

Investigation of like-sign dimuon production in neutrino and antineutrino reactions

Abstract 290 events of the type ν Fe→ μ − μ − X and 53 events from the reaction ν Fe→μ + μ + X with E ν >30 GeV and muon momenta p μ >6.5GeV/ c have been observed in the CDHS detector. After subtracting the background from charged-current processes with one π or K meson of the hadronic shower decaying into μ − ν (or μ + μ) , we obtain for neutrinos a rate of prompt like- sign dimuon production of (3.4±1.8)×10 −5 relative to the rate of charged-current events with the same cuts, or (4.1 ± 2.2)% relative to the prompt μ − μ + rate, and for antineutrinos the corresponding relative rates (4.3±2.3)×10 −5 and (4.2 ± 2.3)%. A possible explanation for the events is charm pair production at a level of 10 −3 relative to all charged-current reactions.

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.

Prism plot analysis of the reaction π+p → pπ+π+π- AT 16 GeV/c: Aachen-Berlin-Bonn-CERN-Cracow-Heidelberg-Warsaw-Collaboration

We have analysed the reaction π + p → pπ + π + π − at 16 GeV/c by means of the prism plot analysis (PPA) as proposed by Pless et al. We have separated ten reaction channels contributing to the final state pπ + π + π − and present the results in terms of partial and differential cross sections, invariant mass and decay angular distributions. We show that the PPA is a self-controlling method which is demonstrated by the emergence of a broad (3π) + enhancement around 1800 MeV decaying into ρ 0 π + .

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.

Prism plot analysis of the reaction π−p→pπ+π−π− at 16 GeV/c

Abstract A prism plot analysis of the reaction π−p→pπ+π−π− at 16 GeV/c has been made and the results are compared with those obtained in a similar analysis of the reaction π+p→ pπ+π+π− at the same energy. The three dominating reaction mechanisms (pion dissociation, reggeon exchange, proton diffraction dissociation) appear to be well separated, while considerable residual overlaps are present inside these classes. The prism plot method is discussed as a means for detecting hidden structures and some evidence is presented for a broad three-pion enhancement around 2 GeV decaying primarily into ϱ0π−.