In this work we study the meson properties in the framework of an effective quark model. We start from the Bethe-Salpeter equation choosing the interaction kernel in nonlocal form with the Gaussian meson vertex function, characterized by a meson size parameter \ (H\). We demonstrate the model’s predictive power by applying it to both light and heavy systems. Key results include a calculation of the \ (⁰ \) decay width and the pion transition form factor \ (F (Q²) \), which reproduces experimental data from low to high \ (Q²\). We further predict the electromagnetic properties of heavy quarkonia, obtaining the two-photon decay widths of \ (c\) and \ (b\) and the radiative decay widths of \ (J/ \) and \ (\), all of which show consistency with available data and other theoretical approaches. The model provides a computationally efficient and unified framework for describing mesons from the light to heavy quark sectors.
Friesen et al. (Tue,) studied this question.