Evolution of twist-three parton distributions in QCD beyond the large N_c limit
Abstract
We formulate a consistent 1/N_c^2 expansion of the QCD evolution equations for the twist-three quark distributions g_2(x,Q^2), h_L(x,Q^2) and e(x,Q^2) based on the interpretation of the evolution as a three-particle quantum-mechanical problem with hermitian Hamiltonian. Each distribution amplitude can be decomposed in contributions of partonic components with DGLAP-type scale dependence. We calculate the 1/N_c^2 corrections to the evolution of the dominant component with the lowest anomalous dimension - the only one that survives in the large-N_c limit - and observe a good agreement with the exact numerical results for N_c=3. The 1/N_c^2 admixture of operators with higher anomalous dimensions is shown to be concentrated at a few lowest partonic components and in general is rather weak.
Keywords
Cite
@article{arxiv.hep-ph/0001130,
title = {Evolution of twist-three parton distributions in QCD beyond the large N_c limit},
author = {V. M. Braun and G. P. Korchemsky and A. N. Manashov},
journal= {arXiv preprint arXiv:hep-ph/0001130},
year = {2014}
}
Comments
14 pages, LaTeX style, 2 figures