Factorization is not violated

TL;DR

The paper addresses the potential threat to QCD factorization from reggeon-like ladder exchanges in inclusive high-energy processes. It analyzes a representative ladder diagram within the CSS factorization framework, introducing a jet subgraph and a remainder to isolate ladder contributions. The main finding is that, upon summing over all final-state cuts, ladder-region contributions cancel at leading power, preserving factorization, with the method extendable to more complex ladder exchanges. The work underscores the robustness of factorization theorems in QCD and motivates a more rigorous, systematic proof approach for general applicability.

Abstract

We show that existing proofs of factorization imply the cancellation of certain multiladder contributions that Gotsman, Levin, and Maor had suggested would invalidate the basic factorization theorem in QCD. No modifications of the original argument are necessary, although the details of the example offer useful insight into the mechanisms of factorization.

Figures (10)

• Figure 1: The uncut version of the graph analyzed in this paper.
• Figure 2: The hard subgraph, represented by a star in our graphs.
• Figure 3: Labeling of momenta for one of the ladder subdiagrams.
• Figure 4: The basic diagram split into subdiagrams $J_{A}$ and $R$ corresponding to our chosen region of the loop momenta.
• Figure 5: The four cuts of subgraph $R$.