Single-pion production in antineutrino-induced neutral-current interactions

Results are presented on antineutrino-induced processes in which a single π⁰or π^? is produced. The raw data come from analysis of film from Gargamelle filled with a propane-freon mixture. Comparison of the neutral-current production rates for π⁰and π^?, after correction for nuclear effects, indicates that pure isoscalar or pure isovector transitions are not favoured. The ratio of the neutral-to-charged-current single-π⁰ production rates is found to be compatible with the static model for Δ³³ resonance production in the framework of the Weinberg-Salam theory, yielding values for sin²θ_W in the range 0.15–0.52.