[en] Results are presented on exclusive single-pion production in the bubble chamber Gargamelle, filled with a light propane-freon mixture, and exposed to a focused wide-band beam at the C.E.R.N. proton synchrotron. The charged and neutral current channels are separately examined for their isospin structure, and for production of the δ(3,3) resonance. A model-independent analysis of the Lorentz structure of the weak neutral current exclusive channels combined with inclusive and semi-inclusive data shows the Salam-Weinberg model to be the only model for weak interactions which is wholly consistent with the data. A simplified nuclear model is used to extract the charged and inelastic neutral current neutron to proton cross-section ratios. (author)

[en] The tracking environment in the H1 Forward Tracker Detector, where the hit multiplicity from proton fragments is high, is parituclarly hostile. The techniques and software which have been developed for pattern recognition and Kalman fitting of charged particle tracks in this region are described in detail. (orig.)

[en] The tracking environment in the H1 Forward Track Detector, where the hit multiplicity from proton fragments is high, is particularly hostile. The techniques and software which have been developed for pattern recognition and Kalman fitting of charged particle tracks in this region are described in detail. (orig.)

[en] Results are presented on antineutrino-induced processes in which a single π⁰ or π^- is produced. The raw data come from analysis of film from Gargamelle filled with a propane-freon mixture. Comparison of the neutral-current production rates for π⁰ and π^-, after correction for nuclear effects, indicates that pure isoscalar or pure isovector transitions are not favoured. The ratio of the neutral-to-charged-current single-π⁰ production rates is found to be compatible with the static model for Δ³³ resonance production in the framework of the Weinberg-Salam theory, yielding values for sin²thetasub(W) in the range 0.15-0.52. (Auth.)

[en] A sample of 766 antineutrino charged current elastic events has been used to extract the variation of the elastic cross section with antineutrino energy and the distribution of dN/dq². The best fit value for the parameter Msub(A) obtained from these measurements is Msub(A)=0.91+-0.04 GeV/c² for Msub(V)=0.84 GeV/c². A simultaneous determination of Msub(A) and Msub(V) gives Msub(A)=0.94 +- 0.07,Msub(V)=0.81+-0.03. (Auth.)

[en] On a selected sample of 2171 events, observed in the big heavy liquid bubble chamber Gargamelle at CERN, the charged current total cross section for antineutrino on nucleons has been determined up to the laboratory energy Esub(anti γ) = 8 GeV. The total cross section is found to be a linear function of the antineutrino energy expressed by sigmasub(tot) (Esub(anti γ)) = (0.26 +- 0.020) X 10^-38 X Esub(anti γ)(GeV) cm². The energy dependence of < q²>sub(anti γ) is found to be given by < q²>sub(anti γ) = (0.15 +- 0.04)Esub(anti γ) + (0.05 +- 0.12) (GeV/c)². With a simplified nuclear model the ratio of cross sections on neutrons and protons has been estimated as a function of energy and for two differnt values of the scaling variable x. The results are compared with the prediction of the naive quark parton model. (Auth.)

[en] A study is made of the ωπ⁰ system produced near threshold in the reaction γp -> π⁺π^-π⁰π⁰p. A spin-parity analysis shows that the ωπ⁰ enhancement is consistent with predominant 1⁺ B(1235) production, with proportional 20% Jsup(P) = 1^- background. (orig.)

[en] The reactions γp -> K⁺K^-π⁰(p) and γp -> Ksub(S)⁰Ksup(+-)πsup(-+)(p) have been measured using tagged photons in the energy range 20 to 70 GeV. No resonance structure is observed in either of the Kanti Kπ invariant mass distributions, which range from threshold up to approx.= 3 GeV. The photoproduction cross section for PHIπ⁰ and Ksup(*)(892)K are presented and are compared with theoretical predictions. No evidence has been found for the photoproduction of PHI'(1680). (orig.)

[en] Further experimental evidence is given for the F meson through its decay into eta's. Results are presented for the decay channels etaπsup(+-), etaπ⁰πsup(+-) and etaπ⁺π^-πsup(+-), and confirm those obtained in a previous experiment. (orig.)

[en] A rhoπ enhancement with mass 1.67 +- 0.02 GeV and width 0.16 +- 0.02 GeV is observed in the channel ßp -> pπ⁺π^-₀. Assuming an incoherent background, the cross section x branching ratio is 100 +- 20 nb. A spin-parity analysis favours Jsup(P) = 1^-. The enhancement is most simply interpreted as a radial recurrence of the ß meson. (orig.)