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

Abstract

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 (NR,NI) are introduced in α-nucleus scattering calculations, and the individual optimized (NR,NI) for all nuclei and energies are searched out under the guidance of χ2 criterion. We systematically explore the energy dependence of NR and NI by considering the α elastic scattering from 12C to 208Pb at incident energies below 120MeV/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.