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We present new break-up and coherent data for h meson photoproduction on the deuteron, using a deuterium target and tagged bremsstrahlung photons up to 1 GeV. The differential cross sections for the coherent process were measured from threshold to 800 MeV. They are much smaller than those previously reported. The break-up channel provides a direct measurement of the neutron to proton differential cross section ratios. At the S 11 ͑1535͒ resonance peak, s n ͞s p 0.68 6 0.06 leading to an isoscalar to isovector amplitude ratio of A s ͞A y 0.096 6 0.02. [S0031-9007 (97)03324-3]

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Analyses of 0.8 and 1 GeV p + ' 'Pb elastic angular distribution data have obtained neutron-proton rootmean-square radius differences (hr") 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 Ar"~= 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. 5' center of mass in order to explore the momentum transfer region from 3.5 to 5.3 fm '. Although the familiar diffraction pattern persists to 42.5', 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. NUCLEAR REACTIONSPb{p,p), E=0.8 GeV, measured g(0); enriched target; resolution = 100 keV, 6~m = 2. 5' to 42.5 . Microscopic optical model analysis using KMT potential; deduced Ar, error analysis and comparison with other results.

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