All-loop calculation of the Reggeon field theory amplitudes via stochastic model

TL;DR

This paper develops a stochastic model approach to compute all-loop Reggeon field theory amplitudes, providing numerical results for Green functions and cross sections, and analyzing the significance of loop diagrams and Pomeron couplings.

Contribution

It introduces a stochastic model method to perform all-loop calculations of RFT amplitudes, including numerical solutions and phenomenological applications.

Findings

Loop contributions are essential for accurate amplitudes.

Changing the Pomeron intercept can mimic loop effects.

Quartic Pomeron coupling is negligible at current energies.

Abstract

The evolution equations for Green functions of the Reggeon Field Theory (RFT) are equivalent to those of the inclusive distributions for the reaction-diffusion system of classical particles. We use this equivalence to obtain numerically Green functions and amplitudes of the RFT with all loop contributions included. The numerical realization of the approach is described and some important applications including total and elastic proton--proton cross sections are studied. It is shown that the loop diagram contribution is essential but can be imitated in the eikonal cross section description by changing the Pomeron intercept. A role of the quartic Pomeron coupling which is an inherent part of the stochastic model is shown to be negligible for available energies.