One pion production in neutrino-nucleon scattering and the different parameterizations of the weak N → Δ vertex

Abstract

The N → Δ weak vertex provides an important contribution to the one pion production in neutrino-nucleon and neutrino-nucleus scattering for πN invariant masses below 1.4 GeV. Beyond its interest as a tool in neutrino detection and their background analyses, one pion production in neutrino-nucleon scattering is useful to test predictions based on the quark model and other internal symmetries of strong interactions. Here we try to establish a connection between two commonly used parameterizations of the weak N → Δ vertex and form factors (FF) and we study their effects on the determination of the axial coupling C A 5 (0), the common normalization of the axial FF, which is predicted to hold 1.2 by using the PCAC hypothesis. Predictions for the νμp → μ-pπ+ total cross sections within the two approaches, which include the resonant Δ++ and other background contributions in a coherent way, are compared to experimental data.