Diffractive neutrino-production of pions on nuclei: Adler relation within the color-dipole description

TL;DR

This paper investigates neutrino-induced pion production on nuclei using the color dipole model, revealing how coherence effects and nuclear breakup influence the validity of the Adler relation across different energies.

Contribution

It introduces a detailed analysis of coherence effects in neutrino-nucleus interactions within the color dipole framework, highlighting energy-dependent violations of the Adler relation.

Findings

The Adler relation is strongly broken at high energies ( u > 10 GeV) due to nuclear effects.

In incoherent processes, the Adler relation is violated at low energies but holds better at higher energies.

Coherence length scales significantly affect the cross sections and the validity of the Adler relation.

Abstract

Effects of coherence in neutrino-production of pions off nuclei are studied employing the color dipole representation and path integral technique. If the nucleus remains intact, the process is controlled by the interplay of two length scales. One is related to the pion mass and is quite long (at low Q^2), while the other, associated with heavy axial-vector states, is much shorter. The Adler relation is found to be broken at all energies, but especially strongly at \nu > 10 GeV, where the cross section is suppressed by a factor ~A^{-1/3}. On the contrary, in a process where the recoil nucleus breaks up into fragments, the Adler relation turns out to be strongly broken at low energies, where the cross section is enhanced by a factor ~A^{1/3}, but has a reasonable accuracy at higher energies, where all the coherence length scales become long.