Single pion production in charged current$\bar vD$ interactions at high energies

Abstract

The reactions$\bar vD \to \mu ^ + n\pi ^ - (p_s )$ and$\bar vD \to \mu ^ + p\pi (n_s )$ have been studied at antineutrino energies varying from 5 to 200 GeV. The cross sections for these reactions were determined from 545 and 300 selected events for each channel respectively. The first reaction was used for the study of the decay properties of the Δ resonance that dominates this channel. The experimental results have been compared with the theoretical predictions of Rein and Sehgal [9] and of Fogli and Nardulli [10]. Using the first model we obtained for the axial form factor parameterM _a =1.01±0.05 GeV/c². With this value the model is in agreement with the experimentaldσ/dQ ² distributions forQ ²>0.25 GeV² and with the distributions of the invariant hadronic massW. The isospin structure of the one-pion production has been investigated and compared with the results of other experiments.