Factorization of tree QCD amplitudes in the high-energy limit and in the collinear limit
Loading...
Date
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Description
In the high-energy limit, we compute the gauge-invariant three-parton forward clusters, which in the BFKL theory constitute the tree parts of the NNLO impact factors. In the triple collinear limit, we obtain the polarized double-splitting functions. For the unpolarized and the spin-correlated double-splitting functions, our results agree with the ones obtained by Campbell-Glover and Catani-Grazzini, respectively. In addition, we compute the four-gluon forward cluster, which in the BFKL theory forms the tree part of the NNNLO gluonic impact factor. In the quadruple collinear limit we obtain the unpolarized triple-splitting functions, while in the limit of a three-parton central cluster we derive the Lipatov vertex for the production of three gluons, relevant for the calculation of a BFKL ladder at NNLL accuracy. Finally, motivated by the reorganization of the color in the high-energy limit, we introduce a color decomposition of the purely gluonic tree amplitudes in terms of the linearly independent subamplitudes only.
LaTeX, 52 pages, 8 figures. Typos in eq.(2.3) and (2.7) corrected. One citation added in ref.[13]
LaTeX, 52 pages, 8 figures. Typos in eq.(2.3) and (2.7) corrected. One citation added in ref.[13]