Infrared Approach to Large-Angle Scattering at Very High Energies

The hypothesis is investigated that the observed exponential decrease of the elastic large-angle high-energy proton-proton cross section is a consequence of soft-meson emission in strong interactions at very high energies. This interpretation is suggested by the observation of leading particles and low c.m. energies of the secondary mesons in cosmic-ray collisions. Neglecting the recoil of the soft mesons implies the factorization of the cross section into a potential part and an infrared part which is given by Poisson's distribution law. These properties alone provide a number of interesting experimental predictions. Adding the assumption of asymptotic dilatation invariance determines the energy dependence of the potential cross section and yields new results: The magnetic form factor $G_M\mathrm{}\left(t\right)\mathrm{}$ of the nucleon becomes a simple function of the multiplicity of soft mesons produced in quasi-elastic electron-nucleon scattering. If this relation can be confirmed experimentally, it will provide a new method of measuring electromagnetic form factors at very high energies. Furthermore, the factor $\exp (-\overline{n})$ of the Poisson distribution can account for the exponential decrease of the elastic proton-proton cross section, and this interpretation gives several new experimental predictions.