Chiral Symmetry and Neutrino Pion Production off the Nucleon

TL;DR

This paper introduces a chiral symmetry-based model for neutrino-induced pion production off nucleons, highlighting the importance of background terms alongside the Delta resonance, and discusses their impact on cross sections and parity violation effects.

Contribution

The study incorporates background terms mandated by chiral symmetry into neutrino pion production models, revealing their significant influence on cross sections and parity-violating observables.

Findings

Background terms significantly affect pion production cross sections.

Interference between non-resonant and Delta terms induces parity-violating effects.

Model results are relevant for neutrino oscillation experiments.

Abstract

The neutrino pion production off the nucleon is traditionally described in the literature by means of the weak excitation of the Delta(1232) resonance and its subsequent decay into N pi. Here, we present results from a model that includes also some background terms required by chiral symmetry. We show that the contribution of these terms is sizeable and leads to significant effects in total and partially integrated pion production cross sections at intermediate energies of interest for neutrino oscillation experiments. Finally, we discuss parity-violating contributions to the pion angular differential cross section induced by the interference of these non-resonant terms with the Delta piece.