New determination of the $N$-$\Delta(1232)$ axial form factors from weak pion production and coherent pion production off nuclei at T2K and MiniBooNE energies revisited

TL;DR

This paper revisits the axial form factors of the N-Delta(1232) transition by re-evaluating model predictions with an improved fit to old data, resulting in increased cross section estimates and highlighting tensions with recent experimental ratios.

Contribution

It provides a revised determination of the N-Delta axial form factors using an improved fit to historical data, updating previous model predictions.

Findings

20%-30% increase in total cross sections

Compatibility within 1σ of previous results

Identifies tension between experimental ratios and theoretical predictions

Abstract

We re-evaluate our model predictions in Phys. Rev. D 79, 013002 (2009) for different observables in neutrino induced coherent pion production. This comes as a result of the new improved fit to old bubble chamber data of the dominant axial C_5^A nucleon-to-Delta form factor. We find an increase of 20%-30% in the values for the total cross sections. Uncertainties induced by the errors in the determination of C_5^A are computed. Our new results turn out to be compatible within about $1\sigma$ with the former ones. We also stress the existing tension between the recent experimental determination of the \sigma(CC coh \pi^+)}/\sigma(NC coh \pi^0)} $ ratio by the SciBooNE Collaboration and the theoretical predictions.