Monochromatic and polarized gamma ray beams for the study of the three-body system

Particular attention has been paid to the study of the γ3He → pd reaction in the γ-energy region between 200 and 400 MeV, where non-nuclear degrees of freedom are expected to give relevant effects. Sharp enhancements in the cross section, associated with the formation of a Δ(1232) intermediate state or with the excitation of three baryon resonances, have not been observed, but Meson Exchange Currents and Δ(1232) contributions must be included in the theoretical calculations to provide a qualitative and quantitative agreement with the experimental data. In the same context, very recently the three-body break-up process has been explored. (orig./WL)