Associated production by weak charged and neutral currents

Cross-section estimates are presented for the charged- and neutral-current associated-production reactions ${\nu }_{\mu }N\to \mathrm{lK}\Lambda$ and ${\nu }_{\mu }N\to \mathrm{lK}\Sigma$, where $l=\mu or {\nu }_{\mu }$, respectively. The neutral-current reactions are considered within the framework of the Weinberg-Salam theory and theories in which the hadronic neutral current is proportional to the electromagnetic current. The calculations are performed using the Born approximation for the range of incident neutrino energies relevant for present experiments, from threshold to 3 GeV. We find flux-averaged cross sections much smaller than those indicated by preliminary Argonne data. Finally, calculations of the longitudinal polarization of the hyperons are presented.