A comprehensive formalism is presented to describe the photo- or electroproduction of mesons off the nucleon. Taking the hadrons as extended objects described by form factors, we discuss the issues of gauge invariance and of off-shell form factors (both hadronic and electromagnetic). Specifically, we show how the gauge invariance of the production current is preserved by introducing auxiliary currents which take the place of the exchange currents usually neglected entirely in practical applications. The relation of the present formulation to tree-level-type prescriptions is discussed. Applications to kaon photoproduction are shown.
|Number of pages||8|
|Journal||Acta Physica Polonica B|
|Publication status||Published - 2000|