Haberzettl, H (reprint author), George Washington Univ, Inst Nucl Studies, Washington, DC 20052 USA.
Considering single-meson photo-and electroproduction off a baryon, it is shown how to restore local gauge invariance that was broken by replacing standard Feynman-type meson exchange in the t channel by exchange of a Regge trajectory. This is achieved by constructing a contact current whose four-divergence cancels the gauge-invariance-violating contributions resulting from all states above the base state on the Regge trajectory. To illustrate the procedure, modifications necessary for the process gamma + p -> K+ + Sigma(*0) are discussed in some detail. We also provide the general expression for the contact current for an arbitrary reaction.