The first-order optical potential evaluation for the elastic scattering of neutron on the bound system using the impulse approximation method.

The method of impulse approximation is used to check the validity of the first-order optical potential for the elastic scattering problem of the neutron on the bound system, namely, C 1 2 (n. n) C 1 2 , Ca 4 0 (n , n) Ca 4 0 and Pb 2 0 8 (n , n) Pb 2 0 8 at incident neutron energies of 155 and 225 MeV. The optical potential is derived as the first-order term within the spectator expansion of a nonrelativistic multiple scattering terms using the Lippmann–Schwinger equation. The Modern realistic two-body potential ArgonneV18 in the momentum space was used as input in the Lippmann–Schwinger equation. The obtained results for the elastic differential cross-sections are in a good agreement with the experimental data taken from EXFOR Database for all studied targets at neutron energy above 200 MeV. As the neutron energy decreases down to approximately 155 MeV, the discrepancies with experimental data appear, which is in accordance with the impulse approximation formalism. [ABSTRACT FROM AUTHOR]