Effects of direct reaction coupling in compound reactions

The Hauser-Feshbach (HF) model with width fluctuation correction needs to be modified when strongly coupled direct reaction channels exist. We perform cross section calculations for compound reactions which include strongly coupled channels (direct), based on the Kawai-Kerman-McVoy (KKM) theory. In KKM the cross sections are expressed in terms of channel matrix, which is given by the coupled-channels method. Numerical calculations are given for the U-238 elastic scattering cross sections, and the elastic enhancement factor. It is shown that the compound elastic cross sections are affected by the direct channels when the coupling is strong.