This paper gives the results of a study of single-pion production by the weak charged current utilizing the wide-band muon-type-neutrino beam at the Argonne Zero Gradient Synchrotron. The data were obtained from hydrogen and deuterium fillings of the 12-ft bubble chamber. The methods of event selection and separation from background are given as are the details of the corrections and systematic effects in the data sample. The energy-dependent cross sections and differential distributions are presented for the three single-pion production reactions vp -p p y + , vn +p and vn -p -n r f . An isospin decomposition shows that the ratio of I = , to I = amplitudes is 0.68k0.04 with a relative phase of (90.7k4.6)" for M ( N a ) < 1.4 GeV. This agrees with theoretical models, particularly the detailed calculation of Adler. Using the data of the reaction vp -p-pa+, the characteristic mass of the nucleon axial-vector elastic form factor is measured to be 0.98' ::;GeV when analyzed within the context of the Adler model. The data are also compared to other parametrizations of the nucleon axial-vector form factor. 1161

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This paper reports a determination of the axial-vector form factor of the nucleon using the momentum-transfer distribution for 1737 events of the type vPd+p-pps. The events were obtained from a 2 . 4~ lo6-frame exposure of the Argonne 12-foot bubble chamber to a neutrino beam at the Argonne Zero Gradient Synchrotron. After fitting and applying selection criteria, the background was estimated to be at the 2% level. The axial-vector mass in the dipole parametrization was measured to be MA = 1.00k0.05 GeV/c2, in good agreement both with earlier measurements from this experiment and with other recent results. A test of the conserved-vector-current hypothesis, made by simultaneously fitting MA and M v using dipole form factors, gave MA =0.80+0.10 GeV/c2 and MV=0.96 k0.04 Gev/c2.

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