Nonperturbative features of the axial current

TL;DR

This paper investigates the nonperturbative structure of the axial current using the instanton vacuum model, providing insights into light-cone distribution amplitudes relevant for high-energy physics phenomena.

Contribution

It introduces a method to evaluate axial distribution amplitudes within the instanton vacuum model, including a code and interpolation formula for practical use.

Findings

Derived nonperturbative axial DAs related to pions.

Provided a computational tool for evaluating these DAs.

Established relevance for neutrino interactions and heavy quark decays.

Abstract

We study the nonperturbative structure of the axial current and evaluate the two-point light-cone distribution amplitudes (DA) associated with the correlator \int d\xi exp(-iq\xi)<0|\bar{\psi}(x)\Gamma\psi(y)J_{\mu}^{5}(\xi)|0> within the instanton vacuum model in the leading order in O(1/N_c). Due to the built-in chiral symmetry, four of eight axial DAs are related to that for pions. Knowledge of these nonperturbative objects is important for phenomenological study of high-energy neutrino interactions and semileptonic decays of heavy quarks. We provide a code for evaluation of these DAs and an interpolation formula valid in the region Q^2 < 1 GeV^2.