Coupled-channel Optical Model With Dispersion Relation

A consistent analysis for nuclear level structure and nucleon scattering data up to 200 MeV was performed for sd-shell nuclei, using a unified framework of soft-rotator model and coupled-channels approach. The soft-rotator model parameters were determined so as to reproduce measured collective levels. Based on the nuclear wave function, the coupling scheme is built. As to ^28,30Si and ^24,26Mg, the calculation showed good agreement with experimental data for both collective levels and nucleon interaction data — neutron total cross sections, proton reaction cross sections, and nucleon scattering angular distributions.The dispersion relation is implemented into optical potential. The number of potential parameters is greatly reduced, compared to the common coupled-channel optical model. And a uniform optical potential for the bound state and the scattering state is constructed, the analytic result for the integrals of the dispersion relation is derived and compared with that of numerical solution.The dispersive coupled-channel method based on soft rotator model is used to re-analyze the scattering data of deformed ²⁸Si induced by neutron or proton. A set of dispersive optical potential parameters is obtained, and a good agreement with measurements is seen for the calculated neutron total, neutron/proton elastic and inelastic angular distribution.