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We present results on the experimental study of inelastic charged-current antineutrino-nucleon scattering in the energy range of 10–200 GeV. The data sample, consisting of about 6500 antineutrino-induced events, was obtained in the Fermilab 15 ft bubble chamber filled with a heavy neon-hydrogen mixture. The differential cross sections for ν μ N interactions are presented in terms of scaling variables x and y . The structure functions F 2 ν and xF 3 ν have been evaluated as functions of x and E ν . A deviation from the scaling hypothesis, similar to those found in other experiments on inelastic lepton-nucleon scattering, has been observed. The data are interpreted in the framework of the quark-parton model. Quark and antiquark distributions and their energy dependences are presented.
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The reaction π−A→Aπ− γ at 40 GeV/c was studied on “Sigma” spectrometer on six different nuclear targets in the region of four-momentum transfer |t|<0.05 (GeV/c)2. A phenomenon of elastic scattering of pions on the nuclear Coulomb field photons was observed, its total and differential cross sections were measured. The cross section of Compton effect on π−-meson was measured.
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Results of the first experiments with the Neutral Detector at the electron-positron storage ring VEPP-2M are presented. Branching ratios of the ø-meson radiative decays have been measured: B ( ø → ηγ )=(1.30±0.06)%, B ( ø → π 0 γ )=(0.130±0.013)%, their accuracy being several times higher than the world average. The width ratio is Γ(ø→ηγ) Γ(ø→π 0 γ)=(10±1) . Using the abovementioned quantities, the ω − ø mixing angle θ v =(38.3±0.2) ° , as well as the ratio between the effective magnetic moments of the s- and u-quarks, μ s μ u =(0.57±0.03) have been calculated.
CROSS SECTIONS IN THE PHI MESON PEAK (CORRECTED FOR RADIATIVE EFFECTS).
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SAME AS FIG 2A, BUT KINEMATICAL RECONSTRUCTION ARE APPLIED. I.E. THE ENERGY- MOMENTUM CONSERVATIONS ARE USED TO IMPROVE THE ACCURACY OF PARTICLE ENERGIES AND ANGLES MEASURED IN DETECTOR.
Direct photon production in hadronic events from e+e− annihilation has been studied at s=29 GeV with use of the MAC detector at the PEP storage ring. A charge asymmetry A=(−12.3±3.5)% is observed in the final-state jets. The cross section and the charge asymmetry are in good agreement with the predictions of the fractionally charged quark-parton model. Both the charge asymmetry and total yield have been used to determine values of quark charges. Limits have been established for anomalous sources of direct photons.
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A search for supersymmetric electron production via the reaction e+e−→e±γ̃ẽ∓ followed by the decay ẽ∓→e∓γ̃ has been performed with the MAC detector at the electron-positron storage ring PEP. No candidates were found in a sample corresponding to an integrated luminosity of 36.4 pb−1. For a massless γ̃ this corresponds to a lower limit on the ẽ mass of 22.4 GeV/c2 at the 95% confidence level.
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The reactions e + e − →γγγ and e + e − →γγγγ have been studied at center-of-mass energies between 35 and 46.8 GeV with an integrated luninosity of about 130 pb −1 accumulated with the CELLO detector at PETRA. The measurements are compared to QED calculations up to third and fourth orders of perturbation theory. Excellent agreement is observed.
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