Microscopic optical potential forα-nucleus elastic scattering in a Dirac-Brueckner-Hartree-Fock approach

Abstract

The microscopic optical model potential (OMP) of $\ensuremath{\alpha}$-nucleus elastic scattering based on a double-folding model (DFM) is studied. The nucleon OMPs in nuclear matter as well as the nucleon-nucleon ($\mathit{NN}$) effective interaction are calculated in the framework of the Dirac-Brueckner-Hartree-Fock (DBHF) approach, in which the density and energy dependence is parametrized by polynomial expansions. The microscopic OMP of nucleus-nucleus scattering is obtained by doubly folding the complex $\mathit{NN}$ effective interaction with respect to the densities of both projectile and target nuclei. An improved local-density approximation is adopted to take account of the finite-range correction. Renormalization factors on the real and imaginary OMP are introduced to obtain the best fit to the experimental data. A systematic analysis of $^{4}\mathrm{He}$ elastic scattering off $^{12}\mathrm{C}$, $^{16}\mathrm{O}$, $^{28}\mathrm{Si}$, and $^{40}\mathrm{Ca}$ is performed. The calculated cross sections over a wide range of incident energies and scattering angles are in good agreement with the experimental data, which confirms the applicability of this model. Moreover, for the same projectile and target, the renormalization factors are found to be almost constant at various incident energies.