The production of strange particles in π + d interactions has been examined at 4 GeV/ c where no previous data exist. Careful attention has been given to the resolution of ambiguities and to corrections for losses in a total sample of about 22 000 events which have been used to determine channel cross sections. Where they can be checked, the cross sections fit well into the observed variation of existing cross sections at higher and at lower energies.
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We have measured inclusive γ and π0 production in multiprong events produced by e+e− annihilation in the center-of-mass energy range 4.9 to 7.4 GeV. We find the π0 inclusive cross section to be consistent in shape and normalization with half the charged-π cross section between x=0.15 and 0.60, with an integrated inclusive cross-section ratio of σ(π0)|σ(π+)+σ(π−)|=0.47±0.10.
NUMERICAL VALUES OF DATA FROM THIS EXPERIMENT HAVE NOT BEEN KEPT (M. L. PERL, PRIV COMM, 3 MAY 1979).
The ratio R of inclusive π + π − production at low transverse momenta is measured in π + n and pn interactions at 195 GeV/ c . R ( 1 R ) in the proton (neutron) fragmentation region increases with Feynman- x and is smaller than R from π + fragmentation. The results agree with a quark-quark scattering model originally proposed for “hard” processes and disagree with a modified version of the model which includes gluon scattering.
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Measurements of the invariant cross section Ed3σd3p are presented for the production of hadrons (π, K, p, and p¯) at large transverse momentum (p⊥) by 200-, 300-, and 400-GeV protons incident on H2, D2, Be, Ti, and W targets. The measurements were made at a laboratory angle of 77 mrad, which corresponds to angles near 90° in the c.m. system of the incident proton and a single nucleon at rest. The range in p⊥ for the data is 0.77≤p⊥≤6.91 GeV/c, corresponding to values of the scaling variable x⊥=2p⊥s from 0.06 to 0.64. For p−p collisions, the pion cross sections can be represented in the region x⊥>35 by the form (1p⊥n)(1−x⊥)b, with n=8 and b=9. The ratio of π+ to π− production grows as a function of x⊥ to a value larger than 2 at x⊥≳0.5. The ratios of the production of K+ and protons to π+ and of K− and antiprotons to π− also scale with x⊥ for p−p collisions. The K±, p, and p¯ fitted values for n and b are given. Particle ratios are also presented for D2, Be, Ti, and W targets and the dependences on atomic weight (A) are discussed.
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The measurement of the proton-proton total cross section performed by the CERN-Pisa-Rome-Stony Brook Collaboration at the CERN ISR is discussed in detail. The total interaction rate, the elastic scattering rate in the forward direction, and the machine luminosity were measured simultaneously to obtain three different determinations of the total cross section. Consistent results were found, which made it possible to prove the reliability of the Van der Meer luminosity calibration within +-0.9% and to achieve a precision of +-0.6% in the measurement of the total cross section.
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We present results for the differential cross sections of neutrinos and antineutrinos on nucleons in the energy range E = 2−200 GeV, from the BEBC and Gargamelle experiments. The structure functions F 2 , 2 χF 1 and χF 3 have been evaluated as a function of χ and q 2 . Deviations are observed from Bjorken scaling, which are very similar to those found in electron and muon inelastic scattering. For the Callan-Gross ratio, we find 2χF 1 F 2 = 0.80 ± 0.12 and the corresponding value for 〈R〉 = 〈 σ S σ T 〉 = 0.15 ± 0.10 . Our results are consistent with the Gross-Llewellyn-Smith sum rule; we measure ⩾2.5 ± 0.5 valence quarks per nucleon. Quark and antiquark distributions are given. The Nachtmann moments of F 2 and χF 3 are quantitatively consistent with the predictions from QCD. The value of the strong interaction parameter is λ = 0.74 ± 0.05 GeV without corrections, and 0.66 ± 0.05 GeV including α S 2 corrections. The moments of the gluon distribution are found to be positive and indicate an χ distribution of gluons which is comparable with that of the valence quarks.
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We present proton-nucleus dimuon-production cross sections for masses between 4 and 15 GeV, center-of-mass rapidities between -0.23 and 0.6 and incident energies of 200, 300, and 400 GeV. The data confirm scaling to the 20% level. The dependence of continuum 〈pT〉 on beam energy is also presented.
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We report on inclusive hadron production in e+e− annihilation at 〈s〉=53 GeV2, using a small solid-angle magnetic spectrometer with good particle identification at 90° to the beams at SPEAR II. The cross sections of π± and K± when compared with data at s=23 GeV2 exhibit scaling in (sβ)dσdx with x=2Es12. The invariant cross section depends on the momentum as p−4.
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We present data on inclusive negative-hadron production from charged-current antineutrino interactions in a 21% Ne-H mixture. Inclusive single-particle distributions are presented and are shown to be insensitive to the momentum transferred to the hadron vertex. Comparisons made to inclusive data from π−p and π−n interactions indicate a close similarity between the hadrons resulting from π-nucleon and ν¯-nucleus interactions. The general features of the ν¯-nucleus data are found to be similar to those seen in ν¯p interactions. This last observation implies that ν¯p and ν¯n interactions are similar and that nuclear effects are small.
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