High-Energy Hadron-Nucleus Collisions. I. Protons

A semiclassical theory is developed to describe high-energy (≳10 BeV) reactions of hadrons with large nuclei. Coulomb phase effects are important, and they are accurately included in the formulas obtained. The theory is applied to data of Bellettini et al. at CERN for scattering of 19.3-BeV/c protons on large nuclei. Semiquantitative agreement of theory and experiment is obtained. However, for the case of a lead target, variation of the parameters in the theory did not produce a theoretical curve which agreed with the experimental $p$-Pb differential cross section over the entire range of angles measured. To obtain agreement at the smallest angles (before the first diffraction dip), it seems necessary to assume a much more diffuse nuclear surface than is indicated by electron scattering data. This is the regime in which the theory should be most reliable. To reproduce the oscillations in the data at larger angles, one seems forced to assume a fairly sharply defined surface, only slightly more diffuse than electron scattering suggests. Reasons are given why the effective nucleon density may be more diffuse for proton scattering than for electron scattering. Further experiments are suggested.