MEAN-FIELD CALCULATIONS OF NUCLEON-NUCLEUS SCATTERING

Corrections to the first order term of the multiple scattering expansi on of the nucleon-nucleus optical potential due to the propagation of the projectile nucleon in the target nucleus mean held are estimated. The effects of nonlocalities of the nucleon-nucleon transition amplitu de are included. Calculations are performed for nucleon scattering fro m O-16 and Pb-208 at 100, 200 and 400 MeV incident energies. We show t hat the mean field effect is repulsive and reduces the strength of the local representation of the impulse approximation potential by approx imately 25% in the nuclear interior.