Soft High Energy Scattering in Nonperturbative QCD

TL;DR

This paper investigates soft high energy scattering in nonperturbative QCD using a functional integral approach, calculating hadronic amplitudes from Wilson loops and analyzing elastic pp scattering and exclusive π0 production, highlighting the potential observation of the soft odderon.

Contribution

It introduces a functional integral method to compute high energy scattering amplitudes from Wilson loops, providing new insights into diffractive reactions and odderon effects in QCD.

Findings

Elastic pp scattering cross sections agree with experimental data.

Odderon exchange significantly enhances inelastic π0 production.

Potential to observe the soft odderon at HERA.

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.