Unitarity Corrections in High Energy QCD

TL;DR

This paper advances the perturbative understanding of unitarity in the high-energy limit of QCD by constructing and solving a hierarchy of integral equations for n-gluon t-channel amplitudes up to n=6 within the generalized leading logarithmic approximation. It demonstrates that odd-n amplitudes (n=3,5) reggeize completely as superpositions of lower-n states, while six-gluon dynamics reveal a new reggeization piece and a novel W D2 structure that hints at either a new two-to-six vertex or a nontrivial combination of higher two-to-four vertices, pointing toward an effective reggeon field theory in two transverse dimensions with rapidity as time. The work also derives a perturbative Pomeron-Odderon-Odderon vertex and discusses the role of conformal invariance in the emerging field theory, setting the stage for a conformal-field-theory description of high-energy QCD unitarity corrections. Overall, the results support a structured, conformal EFT of reggeized gluons that could unify high-energy QCD dynamics and guide future nonperturbative and phenomenological explorations. The analysis highlights the intertwined roles of reggeization, vertex building blocks like V_{2→4}, and multi-gluon states in achieving unitary amplitudes at asymptotically high energies.

Abstract

The high energy limit of QCD is investigated in the generalized leading logarithmic approximation. We study unitarity corrections to the BFKL Pomeron containing t-channel states with up to six gluons. Special attention is given to the field theory structure of the corresponding multi-gluon amplitudes. We discuss the transition from two to six gluons in the t-channel.