Proton-deuteron elastic scattering at small momentum transfer from 50 to 400 GeV/c

Proton-deuteron elastic scattering has been measured in the four-momentum transfer squared region $0.013<\mathrm{}\left|t\right|<0.14\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$ and for incident proton beam momenta from 50 to 400 GeV/c. The data can be fitted with the Bethe interference formula. We observe shrinkage of the diffraction cone with increasing energy equal to $(0.94\mathrm{}\pm 0.04)\ln \left(\frac{s}{1} \mathrm{Ge}{\mathrm{V}}^2\right)$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{-2\mathrm{}}$. This shrinkage is greater than that observed in $\mathrm{pp}$ elastic scattering. The ratio of the elastic to the total cross section is approximately 0.1 and independent of energy above ∼ 150 GeV. In order to extract information on $pn$ scattering we fit our data using the Glauber approach and a form factor which is the sum of exponentials. The values we obtain for the slope parameter in $pn$ scattering are sensitive to the details of the inelastic double-scattering term.