Global α - nucleus optical model based on an Dirac Brueckner Hartree Fock approach

The global α -nucleus optical model is studied based on the nucleon self-energies in an Dirac-Brueckner-Hartree-Fock (DBHF) approach. The newly developed nucleon-nucleus optical model CTOM derived from DBHF, is used as the basis to consistently generate the real and imaginary potentials of the α -nucleus optical potential by double-folding model. The same range correction a of the improved local density approximation (ILDA) in CTOM is adopted, which is also suitable to modify the nucleon interaction range in α -nucleus systems. To get better description of experimental data, the re-normalization factors ( N R , N I ) are introduced in α -nucleus scattering calculations, and the individual optimized ( N R , N I ) for all nuclei and energies are searched out under the guidance of χ 2 criterion. We systematically explore the energy dependence of N R and N I by considering the α elastic scattering from 12 C to 208 Pb at incident energies below 120 MeV / nucleon and a simple exponential function is extracted. With this global α -nucleus optical potential, a reasonable description of all available experimental data for α scattering from nuclei is achieved.