Real part of the p-p, p-d, and p-n forward scattering amplitudes from 50 to 400 GeV

Proton-proton and proton-deuteron elastic scattering has been measured for incident laboratory energy from 50 to 400 GeV; minimum vertical-bar t vertical-bar values were, for p-p, 0.0005 (GeV/c)/sup 2/, and for p-d, 0.0008 (GeV/c)/sup 2/. From the differential cross sections we have determined the ratios of the real to imaginary parts of the forward scatteringamplitude, rho/sub p/pand rho/sub p/d, for p-pand p-d scattering. Using a Glauberapproach and a sum-of-exponentials form factor we obtain rho/sub d/n for p-n scattering.