Form factors of radiative pion decays in nonlocal chiral quark models

TL;DR

This paper investigates the form factors of radiative pion decay using nonlocal chiral quark models, comparing results with experimental data, NJL model predictions, and chiral perturbation theory to enhance understanding of low-energy QCD phenomena.

Contribution

It introduces a nonlocal chiral quark model with wave function renormalization to analyze pion decay form factors and low energy constants, providing new insights beyond traditional models.

Findings

Calculated vector form factor F_V(q^2) and axial-vector form factor slope F_A(q^2) at threshold.

Compared model predictions with experimental data and NJL model results.

Estimated low energy constants l_5 and l_6 consistent with chiral perturbation theory.

Abstract

We study the radiative pion decay pi+ -> e+ nu_e gamma within nonlocal chiral quark models that include wave function renormalization. In this framework we analyze the momentum dependence of the vector form factor F_V(q^2), and the slope of the axial-vector form factor F_A(q^2) at threshold. Our results are compared with available experimental information and with the predictions given by the NJL model. In addition we calculate the low energy constants l_5 and l_6, comparing our results with the values obtained in chiral perturbation theory.