Exclusive Photo-and Electroproduction of Mesons in the Gev Region

We consider the reactions γ p → M B, with M B being either K + Λ, K + Σ 0 , or π + n, within a diquark model which is based on perturbative QCD. The model parameters and the quark-diquark distribution amplitudes of the baryons are taken from previous investigations of electromagnetic baryon form factors and Compton-scattering off protons. Reasonable agreement with the few existing photoproduc-tion data at large momentum transfer is found for meson distribution amplitudes compatible with the asymptotic one (∝ x(1 − x)). We present also first results for hard electroproduction of the K + Λ final state. Our predictions exhibit some characteristic features which could easily be tested in forthcoming electroproduction experiments.