Nuclear transparency in α-particle scattering beyond the eikonal approach

An independent, complementary, and unbiased study to calculate the transparency functions beyond the eikonal approach by adding the higher-order (up to the third-order term) noneikonal (NE) corrections, in five different effective optical potentials all of them reproduce well the elastic scattering of intermediate energy α-particles (Εα 140-288 MeV) from the two neighborly nuclei 48Ti and 58Ni. The effects of switching (off/on) the Coulomb potential on the results are studied. The individual and the combined effects of the NE corrections and Coulomb potential are explored in the transparency function for a wide range of the impact parameter 'b' from the nuclear surface towards the nuclear interior. No violation is detected in the flux conservation for the considered projectile incident energy and the impact parameter ranges. It is found that, in some cases, it is not necessarily true, as usually believed, that the Coulomb potential decreases the absorption (less transparency) in the central region of the nucleus, the phenomenon which can be explained by a modification of the balance between the nominal real and imaginary parts of some optical potential in the rather complicate transparency function