Chiral Symmetry and Neutrino Pion Production off the Nucleon

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.
Comment: To appear in the proceedings of 9th International Workshop On Neutrino Factories, Superbeams and Betabeams (NuFact07) August 6-11, 2007, Okayama University, Japan