NEUTRON TRANSITION DENSITIES FOR CA-48 FROM PROTON-SCATTERING AT 200 AND 318 MEV

Differential cross sections and analyzing powers for scattering of 200 and 318 MeV protons have been measured for states of Ca-48 up to 7 Me V of excitation. The data cover c.m. momentum transfers from approxima tely 0.4 to 3.0 fm-1. Neutron transition densities were extracted for the 2(1)+, 3(1)-, 3(2)-, 4(2)+, and 5(1)- states using density-depende nt empirical effective interactions previously calibrated upon elastic and inelastic scattering data for O-16 and Ca-40. The corresponding p roton transition densities were obtained from electron scattering data and held fixed during the analysis. Fits performed to the data for ei ther energy provide excellent predictions for the other. Neutron densi ties fitted to data for either,energy independently agree very well wi th each other and with the densities fitted to both data sets simultan eously. These densities are also consistent with earlier data for 500 MeV protons. The energy independence of the extracted transition densi ties demonstrates that residual errors in the reaction model are compa tible with the error bands estimated by the fitting procedure. Several additional tests of the model dependence of the results were performe d also. The proton and neutron transition densities are compared with calculations based upon the extended random phase dominated by 1p1h co nfigurations, whereas densities requiring substantial 2p2h contributio ns tend to be underestimated.