Color evolution of 2 -> 3 processes
Malin Sjodahl
TL;DR
The paper develops a color-space framework for soft-gluon resummation in 2→3 QCD processes by constructing multiplet-inspired bases in the s-channel to simplify color evolution. It extends known 2→2 results to 2→3 by building complete orthogonal color bases for qq̄→qq̄g, gg→qq̄g, and gg→ggg, and deriving the corresponding soft anomalous dimension matrices. The matrices exhibit diagonal and block-diagonal structures reflecting color exchanges, with sizes 4×4, 11×11, and 22×22, and are validated for symmetry and completeness using computer algebra. These results enable more complete resummation for 2→3 processes and can be extended to more final-state partons, though the complexity requires further theoretical advances in the underlying group theory.
Abstract
The color structure needed for resummation of all colored 2 -> 3 processes is calculated using multiplet inspired s-channel bases. In this way the resulting matrices, describing the color structure, are guaranteed to obey simplifying symmetries.
