Mass and state dependence of the interaction function in the direct-semidirect capture model

In the original direct-semidirect (DSD) model for the radiative capture of nucleons in the region of the giant dipole resonance, the complex particle-vibration coupling function was introduced phenomenologically and the real and imaginary strengths V1 and W1 determined from the comparison of the calculated and rather scarce experimental results. One can, on the other hand, extract an analytical expression for this coupling from the recent formulation of the consistent DSD, in light of which we conclude that the strengths V1 and W1 are both spin and mass dependent. Such dependence has not been known before, while the real and the imaginary parts of the coupling function turn out to be indeed of the volume and the surface peaked shapes, respectively, as used in previous versions of the model. The mass dependence deduced is for the capture to the ground states V1=16.8A1/3 MeV for the real and W1=16.1A1/3 MeV for the imaginary part. (author)