New description of the four-body breakup reaction

We present a novel method of smoothing discrete breakup cross sections calculated by the method of continuum-discretized coupled channels. The smoothing method based on the complex scaling method is tested with success for a Ni-58(d,pn) reaction at 80 MeV as an example of three-body breakup reactions and applied to a C-12(He-6, nn(4)He) reaction at 229.8 MeV as an example of four-body breakup reactions. Fast convergence of the breakup cross section with respect to extending the model space is confirmed. The method is also applied to C-12(He-6, nn(4)He) and Pb-208(He-6, nn(4)He) reactions at 240 MeV/A and compared with the experimental data.