Study of Non-Strange Baryon Resonances with Meson Photoproduction

Abstract

Photoproduction of mesons is an excellent tool for the study of nucleon resonances. Complementary to pion induced reactions, photoproduction on the free proton contributes to the determination of the basic properties of nucleon resonances like excitation energy, decay widths, spin, and the coupling to the photon. Photoproduction from light nuclei, in particular from the deuteron, reveals the isospin structure of the electromagnetic excitation of the nucleon. During the last few years, progress in this field has been substantial. New accelerator facilities combined with state-of-the-art detector technologies have pushed the experiments to unprecedented sensitivity and precision. The experimental progress has been accompanied by new developments for the reaction models, necessary to extract the properties of the nucleon states, and for modern hadron models which try to connect these properties to QCD. The emphasis of this review lies on the experimental side and focuses on experiments aiming at precise studies of the low-lying nucleon resonances.