Structure signatures in proton scattering from Li-9,Li-11

The optical potential and observables for proton-Li-9,Li-11 elastic scattering are calculated microscopically using the single scattering approximation to the Kerman-McManus-Thaler multiple scattering expansion. The importance of the central and spin-orbit terms of the optical potential, and of the core and halo nucleon contributions, is clarified in terms of the momentum space behaviors of the nucleon-nucleon amplitudes and relevant density distributions. Calculations for the Li-9 and Li-11 systems at 60 and 62 MeV/nucleon, respectively, are compared with the available experimental data and with calculations and data for the proton-He-8 system at similar energy. Three-body models of Li-11 are used. The effects of the halo distribution in Li-11 are clearly manifest in the elastic cross section but there are small differences between observables for structure models with realistic two-neutron asymptotic behaviors. Calculations suggest that the Li-9 core structure is not realistically described by simple models.