# Electromagnetic properties of heavy-light mesons

## TL;DR

This paper computes electromagnetic form factors for light and heavy-light pseudoscalar mesons using the Bethe-Salpeter framework, achieving good agreement with experimental and lattice QCD data.

## Contribution

It introduces a flavour-dependent effective charge in the Bethe-Salpeter approach, improving the description of quark-fluon interactions and mass differences.

## Key findings

- Electromagnetic form factors match experimental data for pion and kaon.
- Predicted charge radii of heavy-light mesons agree with lattice QCD.
- Nonperturbative quark-photon vertex is effectively determined.

## Abstract

Within the Bethe-Salpeter framework, we present a computation of space-like electromagnetic form factors for pseudoscalar mesons, including light and heavy-light systems. Our approach employs a flavour-dependent variation of the standard Taylor effective charge, which contains key contributions from the quark-gluon vertices. This effective interaction is a common ingredient of all relevant dynamical equations, and accommodates the crucial mass differences between the various quark flavours. Particular attention is paid to the nonperturbative determination of the quark-photon vertex. The computed electromagnetic form factors for the pion and the kaon mesons show excellent agreement with experimental determinations. In addition, the predictions for the charge radii of heavy-light systems are in overall good agreement with lattice QCD.