Energy Dependence and Surface Contribution of the Nucleon-Nucleus Optical Potential

Abstract

The M3Y folding optical potential (OP) is used to analyze $^{9}$Be (p,p) $^{9}$Be elastic scattering at energies from few to 1000 MeV/nucleon. The M3Y folding-model is used for the real part whereas the volume and surface imaginary parts of OP are taken within the high-energy approximation model that based on the Glauber theory. In addition, the Brieva–Rook approximation is used for the spin-orbit OP. The angular distributions for elastic-scattering cross sections and analyzing powers, reaction, and total cross sections, are calculated using the optical model analysis with the partial-wave expansion method. The results show that these experimental data are reproduced well at a wide range of energy. In addition, clear and interesting energy dependencies are found for the different parts of the OP. A new behavior of the surface imaginary is found at scattering at high energies where the results show that the surface contribution to the imaginary part is very important at high energies as well as at low energies. The volume integrals show systematic energy dependencies. A new energy dependence formula is assumed for M3Y-Paris NN interaction to avoid the negative values of the OP at high energies.