A General Nucleon Nucleus Optical Potential A40 E50 Mev

A global, energy-dependent, Lane-model, nucleon-nucleus optical potential has been determined by fitting (p, n)-IAS angular distributions between 25 and 45 MeV while maintaining the fit obtained by Becchetti and Greenlees to proton elastic-scattering data over a wide mass and energy range, thus firmly establishing the essential validity of the Lane model for nucleon-nucleus optical potentials.

The authors report on the development of new global optical model potentials for nucleon-nucleus scattering at medium energies. Using both Schroedinger and Dirac scattering formalisms, the goal is to construct a physically realistic optical potential describing nucleon-nucleus elastic scattering observables for a projectile energy range of (perhaps) 20 meV to (perhaps) 2 GeV and a target mass range of 16 to 209, excluding regions of strong nuclear deformation. They use a phenomenological approach guided by conclusions from recent microscopic studies. The experimental database consists largely of proton-nucleus elastic differential cross sections, analyzing powers, spin-rotation functions, and total reaction cross sections, and neutron-nucleus total cross sections. They will use this database in a nonlinear least-squares adjustment of optical model parameters in both relativistic equivalent Schroedinger (including relativistic kinematics) and Dirac (second-order reduction) formalisms. Isospin will be introduced through the standard Lane model and a relativistic generalization of that model.