Experimental results on the study of quasielastic reactionsv μ n→μ−p and\(\bar v_u p \to \mu ^ + n\) in the energy range 3–30 GeV are presented in this paper. Spark chamber detector with Al 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-factorF A (Q2). We measured the total cross-sections as a function of energy. The parameterM A =(1.00±0.04) GeV/c2 has been determined under the assumption of the dipole parametrization and CVC hypothesis. Upper limit for the second class currents was estimated.

A study is made of production of single charged pions in the reaction ..nu../sub ..mu../N..--> mu../sup -/N..pi.. in the kinematic region corresponding to scattering of the neutrino by virtual mesons. The total and differential cross sections for this process are calculated numerically for the energies of the neutrino beam at Serpukhov. It is shown that the principal mechanism of production of single charged pions in the model of single-meson exchange is scattering of the neutrino by virtual f and rho mesons. The contribution of virtual pions is two to three orders of magnitude smaller. Study of the reactions ..nu../sub ..mu../N..--> mu../sup -/N..pi.. in the region of single-meson exchange makes it possible to obtain valuable information about the weak f..pi.. and rho..pi.. transitions. The total cross section for the reaction ..nu..N..--> nu..N..pi../sup 0/ is an order of magnitude smaller than for production of single pions in the charged current.

Preliminary results are presented on the determination of the energy dependence of the cross section for quasielastic scattering of muon neutrinos by neutrons, ..nu../sub ..mu../+n..--> mu../sup -/+p, in the region 3< or =E< or =30 GeV. From a combined analysis of the total and differential cross sections we have determined the parameter M/sub A/ = 1.00 +- 0.07 GeV/c/sup 2/. In the overlapping energy region the data are in good agreement with the results of other experiments.

Charged current data of a spark chamber neutrino experiment at the 70 GeV Serpukhov accelerator (10 200 events in the v beam and 3600 events in the v beam with energies up to 30 GeV) have been analyzed. Total neutrino and antineutrino cross sections and v-distributions are obtained.

A search for dimuons produced in a spark chamber experiment in neutrino and antineutrino beams of the Serpukhov accelerator is reported. The clear dimuon signal has been observed in vN interactions. Rv = N(2ω)/N(1ω)⩾ (6.2 ± 1.7) × 10−3 in the energy interval 7.5 ÷ 30 GeV. From antineutrino data we conclude that in the same energy range Rv⩽ 1.1. × 10−2 (90% C.L.).

The search for dimuon production in vN and v̄N interactions at the Serpukhov accelerator was started in December, 1974. Preliminary data after analysis of part of the statistics of the neutrino exposure showed no effect [1, 2]. In further measurements we changed the neutrino spectrum. Namely, we suppressed the low energy part and enriched the high energy part. It was done because similar experiments at Fermilab [3, 4] indicated predominant dimuon production at energies E v ≳ 30 GeV. Fig. 1 shows qualitatively the variation of the neutrino spectra from the first to the second run.