Recombination within multi-chain contributions in pp scattering

TL;DR

This paper investigates how interactions between multiple parton evolution ladders in pp scattering can affect high-energy collisions. By analyzing double logarithmic evolution and introducing a recombination vertex between two ladders, the authors show that most recombinations are infrared-dominated unless rapidity intervals are large enough for BFKL dynamics to elevate the transferred momentum, in which case recombinations near the hard subprocess can imprint correlations in the final state. They discuss generalizations to more ladders, with combinatorial enhancement potentially offsetting color suppression, and connect to semihard diffractive states. The results suggest corrections to the conventional eikonal multiparton framework and highlight the need for beyond-DL and numerical studies.

Abstract

We investigate the evolution of multiple parton chains in proton-proton scattering and show that interactions between different chains may become quite important.

Figures (7)

• Figure 1: Two noninteracting chains: (a) the cross section (energy discontinuity of the scattering amplitude $T_{2 \to 2}$), (b) redrawn as a (uncut) two-ladder exchange diagram. Within each chain, the boxes mark the hard subprocess with largest transverse momenta (production of dijets).
• Figure 2: Two recombinations within the two chains.
• Figure 3: A single cell inside a ladder, below the produced pair of jets.
• Figure 4: Kinematics of a recombination $(14)(23) \to (13)(24)$.
• Figure 5: Another way of drawing Fig.2b