Towards a fully microscopic model of proton-nucleus scattering. Single shot predictions of elastic and inelastic scattering of protons from 65 to 200 MeV

摘要

Effective two nucleon (NN) interactions in the nuclear medium and for protons with energies in the range 65 to 200 MeV, have been defined from an accurate mapping of NN g matrices obtained by solving the Brueckner-Bethe- Goldstone (BBG) equations for infinite nuclear matter at various Fermi momenta to 1.5 fm(sup -1). Then, by folding those effective interactions with the ground state one body (nucleon) density matrix elements (OBDME) of nuclei, we have defined proton-nucleus optical potentials. Those density matrix elements have been obtained with diverse (shell) models for the structure with very large basis space calculations used for light nuclei (to (sup 28)Si). The derived optical potentials are nonlocal, complex, and vary with energy and and have been used in the integro-differential form of the Schroedinger equation to predict differential cross sections, analyzing powers and, in some cases, spin rotations for elastic scattering. Excellent results have been obtained for many energies and for scattering from targets ranging from (sup 4)He to (sup 208)Pb and with but single shot calculations. Fits to the scattering date are very good when the ground state density matrix elements and single nucleon bound states are fixed by analyses of the form factors from elastic electron scattering. A key feature of our analysis method is that it is predictive. No adjustment of any element is made to improve fits to data. The relative motion wave functions that one finds with the nonlocal optical potentials then have been used as the distorted waves in distorted wave approximation (DWA) studies of select inelastic scattering events with light mass nuclei, in particular (sup 12)C and lithium isotopes. The same effective NN interactions were used as the transition operators in those calculations and the relevant nuclear spectroscopy (OBDME for inelastic scattering) have been found from large basis shell model evaluations of the nuclear structure; wave functions of which give good descriptions for many measured longitudinal, transverse electric and transverse magnetic form factors from electron scattering. Excellent results are obtained again with no post facto adjustments. (authors). 26 refs., 9 figs.