Electromagnetic and two-photon transition form factors of the pseudoscalar mesons: An algebraic model computation

TL;DR

This paper presents an algebraic model to compute electromagnetic and two-photon transition form factors of ground-state pseudoscalar mesons, fitting experimental data and making predictions relevant for current and future hadron physics experiments.

Contribution

The study introduces a unified algebraic approach based on Schwinger-Dyson and Bethe-Salpeter equations to analyze all ground-state pseudoscalar mesons, fitting parameters to experimental data.

Findings

Successfully fitted meson charge radii and form factors to experimental data.

Predicted form factors for various mesons across a range of photon momentum-squared.

Provided comparisons with other models and lattice QCD results.

Abstract

We compute electromagnetic and two-photon transition form factors of ground-state pseudoscalar mesons: $\pi,\,K,\,\eta_c,\,\eta_b$. To this end, we employ an algebraic model based upon the coupled formalism of Schwinger-Dyson and Bethe-Salpeter equations. Within this approach, the dressed quark propagator and the relevant Bethe-Salpeter amplitude encode the internal structure of the corresponding meson. Electromagnetic properties of the meson are probed via the quark-photon interaction. The algebraic model employed by us unifies the treatment of all ground-state pseudoscalar mesons. Its parameters are carefully fitted performing a global analysis of existing experimental data including the knowledge of the charge radii of the mesons studied. We then compute and predict electromagnetic and two-photon transition form factors for a wide range of probing photon momentum-squared which is of direct relevance to the experimental observations carried out thus far or planned at different hadron physics facilities such as the Thomas Jefferson National Accelerator Facility (JLab) and the forthcoming Electron-Ion Collider. We also present comparisons with other theoretical models and approaches and lattice quantum chromodynamics.