Exclusive Limit of Inclusive Processes

The Mueller expansion of the forward three-body amplitude is used to deduce an expansion for the elastic two-body scattering amplitude at large angles. The first term in the expansion is compared with the data for large-angle elastic $\mathrm{pp}$ data, and is found to be in good agreement. Under special circumstances it is found that the ratio of the large-angle elastic differential cross section to the total cross section is a universal function of one variable independent of the process.