arXiv:hep-ph/0508307·v2·High Energy Physics — Phenomenology
Gauge invariance in two-particle scattering
B. Borasoy🇩🇪 · P.C. Bruns🇩🇪 · U.-G. Meißner🇩🇪 · R. Nißler🇩🇪
Abstract
It is shown how gauge invariance is obtained for the coupling of a photon to a two-body state described by the solution of the Bethe-Salpeter equation. This is illustrated both for a complex scalar field theory and for interaction kernels derived from chiral effective Lagrangians.
Comments: 16 pages, 2 figures, references added and commented on