Coherent Pions From Neutrino Scattering Off Nuclei

TL;DR

This paper presents a comprehensive model for neutrino-induced pion production off nuclei, incorporating chiral symmetry, nuclear effects, and a reduced axial coupling, resulting in lower cross section estimates.

Contribution

It introduces a novel model that accounts for background terms and medium effects, providing more accurate predictions of coherent pion production cross sections.

Findings

Coherent pion production cross sections are about half of previous estimates.

The model includes background terms mandated by chiral symmetry.

Nuclear medium effects and pion distortion are incorporated.

Abstract

We describe a model for pion production off nucleons and coherent pions from nuclei induced by neutrinos in the 1 GeV energy regime. Besides the dominant Delta pole contribution, it takes into account the effect of background terms required by chiral symmetry. Moreover, the model uses a reduced nucleon-to-Delta resonance axial coupling, which leads to coherent pion production cross sections around a factor two smaller than most of the previous theoretical estimates. Nuclear effects like medium corrections on the Delta propagator and final pion distortion are included.