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A search has been performed for weakly interacting neutral light scalar and pseudoscalar particles in a proton-iron beam dump experiment via the Bethe-Heitler process. No positive signal was observed. Limits are derived on the masses of these particles in the framework of the Standard Model and its minimal supersymmetric extension (MSSM) comparing the experimental results with expectations for Bethe-Heitler e+e− and μ+μ− pair production. The Higgs particle of the SU2L×U1 Standard Theory is excluded for masses in the range mH<0.9 MeV at 95% CL. Limits on light Higgs particles of the MSSM and Peccei-Quinn like axions are derived.

Experimental results on the study of quasielastic reactions vun~#-p and ~,p--,#+n in the energy range 3-30 GeV are presented in this paper. Spark chamber detector with A1 filters has been exposed to the wide-band neutrino and antineutrino beams at Serpukhov. Neutrino and antineutrino data have been used to reconstruct the behaviour of axial-vector form-factor FA(Q2). We measured the total cross-sections as a function of energy. The parameter MA = (1.00 _+ 0.04 ) GeV/c 2 has been determined under the assumption of the dipole parametrization and CVC hypothesis. Upper limit for the second class currents was estimated.

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We present results from the Fermilab 15-ft bubble chamber on the charged-partiele multiplicity distributions produced in high-energy charged-current neutrino-proton interactions. Comparisons are made to yp, ep, up, and inclusive/)/) scattering. The mean hadronic multiplicity (n c ) appears to depend only on the mass of the excited hadronic state, independent of the mode of excitation. A fit to the neutrino data gives (n c ) = (1.09 ± 0.38) + (1.09 ± 0.03) InW 2 .