Sensitivity tests on parameters of the nucleon-nucleus dispersive optical model

Abstract

We have conducted tests of two changes to the formalism of the dispersive optical model (DOM) by making use of a large n+{sup 208}Pb database. One change relaxes the constraint, conventional in DOMs, that the real- and imaginary-volume potentials share the same geometrical parameters. The second change adopts a different functional form for the energy dependence of the surface imaginary potential, which allows its strength to drop off rapidly in the 30{endash}80 MeV region. Radial shapes of the total imaginary potentials for the new DOMs are compared to each other and to those of a microscopic optical model. We also present an improved DOM analysis which models elastic scattering data for n+{sup 208}Pb and n+{sup 209}Bi simultaneously, and which incorporates a newer set of n+{sup 208}Pb total cross-section data. {copyright} {ital 1999} {ital The American Physical Society}