Aspects of Neutrino Interactions (Scattering at small $Q^2$- Region)

TL;DR

This paper explores neutrino interactions at small momentum transfer, emphasizing the role of chiral symmetry and PCAC, and compares theoretical predictions with experimental data for energies above 2 GeV.

Contribution

It applies chiral symmetry and PCAC to analyze neutrino reactions at small $Q^2$, providing new estimates for incoherent background and discussing data features.

Findings

Computed cross sections agree with data for $E_\nu > 2$ GeV

Expected equal yields for neutrinos and antineutrinos in coherent pion production

Presented methods to improve data analysis by estimating incoherent background

Abstract

The article begins with a description of chiral symmetry and its application to neutrino induced reactions. For small $Q^2$ (forward direction) the process is dominated by the amplitute with helicity zero where the pion pole disappears when multiplied with the polarization vector. The remaining part of the amplitude is determined by PCAC. For $E_\nu > 2$ GeV the computed cross sections are in good agreement with data. In coherent pion production we expect equal yields for neutrinos and antineutrinos a relation which for $E_\nu > 2$ GeV is fulfilled. We discuss specific features of the data and suggest methods for improving them by presenting new estimates for the incoherent background.