  A dispersive optical model analysis of p+40Ca and p+48Ca interactions has
been carried out. The real and imaginary potentials have been constrained from
fits to elastic scattering data, reaction cross sections, and level properties
of valence hole states deduced from (e,e'p) data. The surface imaginary
potential was found to be larger overall and the gap in this potential on
either side of the Fermi energy was found to be smaller for the neutron-rich
p+48Ca system. These results imply that protons with energies near the Fermi
surface experience larger correlations with increasing asymmetry.
