Measurement of the Energy Dependence of ElasticπpandppScattering at Large Angles

We have measured ${\pi }^{\pm }p$ and $\mathrm{pp}$ elastic differential cross sections in the range $\left|{cos\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}\right|<\mathrm{}0.35\mathrm{}$ for incident momenta from 2 to 9.7 GeV/c for ${\pi }^{-}p$ and $\mathrm{pp}$ and from 2 to 6.3 GeV/c for ${\pi }^{+}p$. We find that the fixed-c.m.-angle $\pi p$ differential cross sections cannot be described as simple functions of $s$. The data are compared to the energy and angular dependence predicted by the constituent model of Gunion, Brodsky, and Blankenbecler.