24–28 Oct 2022
University of Santiago de Compostela
Europe/Madrid timezone

Neutrino-induced one-pion production revisited: the $\nu_\mu n\to\mu^- n\pi^+$ channel

25 Oct 2022, 15:50
20m
Classroom 3, Facultad de Ciencias de la Comunicación (University of Santiago de Compostela)

Classroom 3, Facultad de Ciencias de la Comunicación

University of Santiago de Compostela

Campus Norte, Av. de Castelao, s/n, 15782 Santiago de Compostela, Spain
Oral Contribution P6 Hadron Structure, Spectroscopy, and Dynamics P6 Hadron Structure, Spectroscopy, and Dynamics

Speaker

ELIECER HERNÁNDEZ GAJATE

Description

Understanding single pion production reactions on free nucleons is the first step towards a correct description of these processes in nuclei, which are important for signal and background contributions in current and near future accelerator neutrino oscillation experiments. We reanalyze our previous studies of neutrino-induced one-pion production on nucleons for outgoing $\pi N$ invariant masses below 1.4 GeV, in order to get a better description of the $\nu_\mu n\to\mu^- n\pi^+$ cross section, for which current theoretical models give values significantly below data,. The $\nu_\mu n\to\mu^- n\pi^+$channel is very sensitive to the crossed $\Delta (1232)$ contribution and thus to spin 1/2 components in the Rarita-Schwinger $\Delta$ propagator. We show how these spin 1/2 components are nonpropagating and give rise to contact interactions. In this context, we point out that the discrepancy with experiment might be corrected by the addition of appropriate extra contact terms and argue that this procedure will provide a natural solution to the $\nu_\mu n\to\mu^- n\pi^+$ puzzle. To keep our model simple, in this work we propose to change the strength of the spin 1/2 components in the $\Delta$ propagator and use the $\nu_\mu n\to\mu^- n\pi^+$ data to constraint its value. With this modification, we now find a good reproduction of the $\nu_\mu n\to\mu^- n\pi^+$ cross section without affecting the good results previously obtained for the other channels. We also explore how this change in the $\Delta$ propagator affects our predictions for pion photoproduction and find also a better agreement with experiment than with the previous model.

Primary authors

ELIECER HERNÁNDEZ GAJATE Juan M Nieves

Presentation materials