Coherent pion production off nuclei at T2K and MiniBooNE energies revisited

TL;DR

This paper revisits the theoretical predictions of coherent pion production off nuclei at T2K and MiniBooNE energies, incorporating a new fit to nucleon-to-Delta form factor data, resulting in increased cross section estimates and analysis of uncertainties.

Contribution

It provides updated model predictions for neutrino-induced coherent pion production using an improved axial form factor fit, and compares these with recent experimental data.

Findings

Total cross sections increase by 20-30% with the new fit.

Differential cross section shapes remain largely unchanged.

Theoretical predictions are consistent within 1 sigma with previous results.

Abstract

As a result of a new improved fit to old bubble chamber data of the dominant axial C_5^A nucleon-to-Delta form factor, and due to the relevance of this form factor for neutrino induced coherent pion production, we re-evaluate our model predictions in Phys. Rev. D79, 013002 (2009) for different observables of the latter reaction. Central values for the total cross sections increase by 20% to 30%, while differential cross sections do not change their shape appreciably. Furthermore, we also compute the uncertainties on total, differential and flux averaged cross sections induced by the errors in the determination of C_5^A. Our new results turn out to be compatible within about 1 sigma with the former ones. Finally, we 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.