High-statistics study ofπ+p,π−p, andppelastic scattering at 200 GeV/c

We have measured ${\pi }^{+}p$, ${\pi }^{-}p$, and $\mathrm{pp}$ elastic scattering at an incident-beam momentum of 200 GeV/c in the region of $-t$, four-momentum transfer squared, from 0.021 to 0.665 (${\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$. The data allow an investigation of the $t$ dependence of the logarithmic forward slope parameter $b\equiv \left(\frac{d}{\mathrm{dt}}\right)\left(\ln \frac{d\sigma }{\mathrm{dt}}\right)$. In addition to standard parametrization, we use functional forms suggested by the additive quark model to fit the measured $\frac{d\sigma }{\mathrm{dt}}$ distributions. Within the context of this model we estimate the size of the clothed quark in the pion and proton. Limits on the elastic-scattering amplitude derived from unitarity bounds are checked, and no violations are observed.