Soft High Energy Scattering in Nonperturbative QCD

Abstract

In this report diffractive high energy reactions are discussed in a functional integral approach where hadronic amplitudes are calculated from vacuum expectation values of lightlike Wegner-Wilson loops. In the first part we calculate elastic differential cross sections for high energy and small momentum transfer elastic proton-proton (pp) scattering which are in reasonable agreement with the experimental data. In the second part we consider exclusive ${\pi }^0$ production in ep-scattering. At high energies photon and odderon exchange contribute to this reaction. We show that odderon exchange leads to a much larger inelastic than elastic ${\pi }^0$ production cross section, dominating the $\gamma$ contribution by orders of magnitude. Observing our process at HERA would establish the soft odderon.

Talk given at the International Conference on Elastic and Diffractive Scattering (EDS 99), Protvino, Russia, 28 June-2 July 1999