Extended direct-semidirect mechanism and the role of multistep processes in fast-nucleon radiative capture

The authors have recently developed an extension of the direct semidirect (DSD) radiative capture model to unstable final stages and have confirmed its utility in explaining the spectrum of γ rays from capture of polarized 19.6 MeV protons on 89Y. It was found that the extended DSD model, supplemented by a Hauser Feshbach contribution, successfully explains the observed γ spectra, angular distributions, and analyzing powers, without requiring additional mechanisms, such as precompound or multistep emission, or nucleon-nucleon bremsstrahlung. In this contribution they show that the model also successfully explains data at higher energies (34 MeV incident protons), and that there is no need for additional contributions other than Hauser-Feshbach at this energy as well