We have measured the inclusive electroproduction of positive and negative hadrons in the quark fragmentation region using the streamer chamber at DESY. Data are presented in terms of the variable z p = p / v in the kinematic region 1.8 < W < 2.8 GeV and 0.3 < Q 2 < 1.4 GeV 2 . The positive hadron distributions contain a strong proton component. After subtraction of the proton component and elastic rho events, the distribution (1/ σ tot ) d σ /d z p for positive and negative hadrons agrees well with the corresponding distribution from e + e − annihilation (DORIS data). This behaviour supports the validity of the quark-parton model at surprisingly low Q 2 and W .
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As a part of the study of the inclusive production of electron pairs in pp collisions at the CERN Intersecting Storage Rings (ISR), a search has been performed for additional photons accompanying J/ψ particles. The results suggest that (43±21)% of the J/ψ's are produced via the photonic decay of one of the χ(3.5) states.
The cross section times branching ratio.
The production of φ mesions is studied in the reaction π+p→π+p K+K− and π+→π+p K0K¯0 at 3.75 GeV/c. A large isotropic component is seen in the production angular distribution for the reaction π+p→π+pφ. The cross sections for the φπ+p and φΔ++ final states are compared with the cross sections for ωπ+p and ωΔ++ at the same momentum.
NORMALIZED TO THE CROSS SECTION FOR PI+ P --> PI+ P PI+ PI-.
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A clear, prompt dimuon signal has been observed in a low-statistics streamer-chamber experiment with 16-GeV/c πp interactions. The good mass resolution makes it possible to identify the contributions from ρ and ω decays and η and ω Dalitz decays. An excess of events is observed in the mass region ∼400-600 MeV which is not accounted for by the above-mentioned decays.
The data with PI+- beam obtained from the combination of PI+ and PI- beams.
Electroproduction of hadrons is studied in the kinematic region W < 2.8 GeV and 0.3 < Q 2 < 1.4 GeV 2 using the DESY streamer chamber. Prong cross sections, charged-particle multiplicities and inclusive π − distributions are presented. The average charged multiplicity is found to be independent of Q 2 in the Q 2 range studied here; however it is lower than in photoproduction. The fraction of forward π − is found to be significantly less in electroproduction than in photoproduction. The 〈 p ⊥ 2 〉 for inclusive π − is, for all x values, similar to that found in photoproduction.
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n p annihilations with ⩾ 3 prongs with an incident antineutron momentum between 0.5 and 0.8 GeV/ c are analysed. We present the topological branching ratios and cross sections, the resonance production rates and possible ϱ-ω interference effects.
CHANNEL FRACTIONS IN <2PI+ PI- PI0> FINAL STATE.
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FOR THE FPRIME A PURE 2+ STATE IS ASSUMED AND ONLY JZ=+1,0,-1 CONTRIBUTIONS ARE CONSIDERED.
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We present results from an experiment studying the production of single particles and jets (groups of particles) with high p ⊥ (transverse momentum) in 200 GeV/ c interactions on a beryllium target. We give a detailed discussion of the ambiguities in the jet definition. The jet and single-particle cross sections have a similar shape but the jet cross section is over two orders of magnitude larger. The events show evidence for the coplanar structure suggested by constituent models, and the momentum distributions of charged particles give strong support to a simple quark-quark scattering model.
NOMINAL CALORIMETER THRESHOLD WAS 3 GEV/C. AT WHICH PT TRIGGER EFFICIENCY SHOULD BE 50 PCT. THIS DATA HAS AN ADDITIONAL 20 PCT. NORMALISATION ERROR.
THIS TABLE REFERS TO JET WITH THRESHOLD OF 3 GEV/C. THE JET PONTS ARE AVERAGED OVER ROUGHLY EQUAL AMOUNTS OF +VE AND -VE BEAMS.
THIS TABLE REFERS TO JET WITH THRESHOLD OF 4 GEV/C. THE JET PONTS ARE AVERAGED OVER ROUGHLY EQUAL AMOUNTS OF +VE AND -VE BEAMS.
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.
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