QCD Reggeon Field Theory for every day: Pomeron loops included

TL;DR

This paper derives a comprehensive evolution equation for high-energy hadronic scattering that includes Pomeron loops, nonlinear effects, and dense hadronic interactions, extending the QCD Reggeon Field Theory to all density regimes.

Contribution

It introduces a new Hamiltonian for QCD Reggeon Field Theory that unifies dilute and dense limits, enabling analysis of scattering processes across all density levels.

Findings

Derived the evolution equation including Pomeron loops.

Recovered known limits (JIMWLK and KLWMIJ) from the new framework.

Applicable to a wide range of scattering processes from dipole-dipole to nucleus-nucleus.

Abstract

We derive the evolution equation for hadronic scattering amplitude at high energy. Our derivation includes the nonlinear effects of finite partonic density in the hadronic wave function as well as the effect of multiple scatterings for scattering on dense hadronic target. It thus includes Pomeron loops. It is based on the evolution of the hadronic wave function derived in \cite{foam}. The kernel of the evolution equation defines the second quantized Hamiltonian of the QCD Reggeon Field Theory, $H_{RFT}$ beyond the limits considered so far. The two previously known limits of the evolution: dilute target (JIMWLK limit) and dilute projectile (KLWMIJ limit) are recovered directly from our final result. The Hamiltonian $H_{RFT}$ is applicable for the evolution of scattering amplitude for arbitrarily dense hadronic projectiles/targets - from "dipole-dipole" to "nucleus-nucleus" scattering processes.