Coupled-channel analysis of nucleon scattering fromsup40Ca up to 80 MeV

Differential cross sections σ(theta) and analyzing powers $A_y$(theta) for neutron scattering to the ground and first $3^{\mathrm{-}}$ excited state of ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ have been measured in the energy range from 11 to 17 MeV. Elastic and inelastic scattering measurements have been obtained for $A_y$(theta) at energies of 11.0, 13.9, and 16.9 MeV, the inelastic scattering data representing the first (n,n’) measurements of $A_y$(theta) for this nucleus. Differential cross sections for (n,n) and (n,n’) have been obtained at 13.9 and 16.9 MeV. Both the σ(theta) and $A_y$(theta) data at 13.9 MeV have been compared with previous measurements at this energy and the agreement is good, typically within less than 3%. These results have been combined with other σ(theta) and $A_y$(theta) data and total cross section ${\sigma }_T$ measurements to form a large set of scattering and reaction data for incident energies up to 80 MeV. This data set, along with σ(theta) and $A_y$(theta) measurements available for proton scattering in this energy range, has been described in the framework of the coupled-channel formalism. This highly constrained analysis has led to a precise determination of geometries, energy dependencies, and deformation parameters. Further analyses, which dealt with simultaneous couplings to low- and high-energy excited states, have led to improved descriptions of the elastic scattering measurements for σ(theta) and $A_y$(theta) at backward angles. These results confirm that real and virtual excitations of giant resonances cannot be ignored in the description of the reaction mechanism. In this context, it has also been found that corrections to the real central potentials, as estimated by Mahaux and Ngo^ from dispersion relations, help to further improve the fits to elastic scattering observables.