Study of the Radivative Pion Decay

TL;DR

This paper investigates the radiative decay of charged pions using chiral perturbation theory and light front quark models, calculating form factors, decay rates, and constraining tensor interactions.

Contribution

It provides a comprehensive calculation of the pion's vector and axial-vector form factors across all momentum transfers using two theoretical frameworks.

Findings

Calculated decay branching ratios consistent with experimental data.

Evaluated momentum-dependent form factors for the pion to gamma transition.

Constrained the possible size of tensor interactions in the light front quark model.

Abstract

We study the radiative pion decay of $\pi ^{+} \to e^{+}\nu_{e}\gamma$ in the chiral perturbation theory (ChPT) and light front quark model (LFQM). The vector and axial-vector hadronic form factors ($F_{V,A}$) for the $\pi\to\gamma$ transition are evaluated in the whole allowed momentum transfer. In terms of these momentum dependent form factors, we calculate the decay branching ratio and compare our results with the experimental data and other theoretical predictions in the literature. We also constrain the possible size of the tensor interaction in the LFQM.