Study of neutrino interactions in hydrogen and deuterium. II. Inelastic charged-current reactions

Abstract

This paper gives the results of a study of inelastic charged-current interactions of muon-type neutrinos with hydrogen and deuterium targets using the Argonne 12-foot bubble chamber. We discuss in detail the separation of the events from background. For the single-pion production reactions $\ensuremath{\nu}p\ensuremath{\rightarrow}{\ensuremath{\mu}}^{\ensuremath{-}}p{\ensuremath{\pi}}^{+}$, $\ensuremath{\nu}n\ensuremath{\rightarrow}{\ensuremath{\mu}}^{\ensuremath{-}}n{\ensuremath{\pi}}^{+}$, and $\ensuremath{\nu}n\ensuremath{\rightarrow}{\ensuremath{\mu}}^{\ensuremath{-}}p{\ensuremath{\pi}}^{0}$, energy-dependent cross sections, differential cross sections, invariant-mass distributions, and the ${\ensuremath{\Delta}}^{++}(1236)$ decay angular distribution are presented. These data are also used to study the isospin properties of the $\ensuremath{\pi}N$ system. Comparisons of the data with models of single-pion production are made, and a direct test of partial conservation of the axial-vector current is discussed. Cross sections and invariant-mass distributions are given for the reactions in which more than one pion is produced. Ten events of strange-particle production were found, and the properties of these events are discussed. The energy dependence of the total $\ensuremath{\nu}p$ and $\ensuremath{\nu}n$ cross sections from threshold to 6 GeV was determined, and the $\frac{\ensuremath{\sigma}(\ensuremath{\nu}n)}{\ensuremath{\sigma}(\ensuremath{\nu}p)}$ ratio measured. This ratio and the inclusive $x$ and $y$ distributions rapidly approach the scaling distributions expected from the quark-parton model.