On the pion distribution amplitude. Derivation, properties, predictions

TL;DR

This paper analyzes the pion distribution amplitude using Gegenbauer representations, predicts the pion-photon transition form factor with light-cone sum rules, and compares various models with experimental data.

Contribution

It introduces a detailed analysis of the pion distribution amplitude with two Gegenbauer representations and assesses their impact on form-factor predictions.

Findings

Endpoint behavior of distribution amplitudes is crucial for form-factor predictions.

Predictions for the $ ext{π-γ}$ transition form factor are consistent with experimental data.

Different pion distribution amplitudes significantly affect the form-factor calculations.

Abstract

We provide an in-depth analysis of the $\pi$ distribution amplitude in terms of two different Gegenbauer representations. Detailed predictions for the $\pi-\gamma$ transition form factor are presented, obtained with light-cone sum rules. Various $\pi$ distribution amplitudes are tested and the crucial role of their endpoint behavior in the form-factor analysis is discussed. Comparison with the data is given.