0.8 GeV p+208Pb elastic scattering and the quantity Δr/sub n/p

Analyses of 0.8 and 1 GeV p+208Pb elastic angular distribution data have obtained neutron-proton root-mean-square radius differences (Δr/sub n/p) which are not consistent. Therefore, the 0.8 GeV experiment was repeated using a high resolution spectrometer. The new higher precision data are consistent with the older data, apart from a 15% overall normalization difference. A second order Kerman-McManus-Thaler optical model analysis of the new data, using a model-independent neutron density, yields Δr/sub n/p=0.14 +- 0.04 fm, in good agreement with the most recent result obtained (0.16 +- 0.05 fm) from a similar analysis of the older 0.8 GeV data. In addition, the elastic angular distribution was extended to 42.50 center of mass in order to explore the momentum transfer region from 3.5 to 5.3 fm-1. Although the familiar diffraction pattern persists to 42.50, it was not possible within the framework of our application of the Kerman-McManus-Thaler optical model to fit the data even qualitatively at the larger momentum transfers