English

Two-loop evolution equations for flavor-singlet light-ray operators

High Energy Physics - Phenomenology 2019-03-27 v1 High Energy Physics - Theory

Abstract

QCD in non-integer d=42ϵd=4-2\epsilon space-time dimensions enjoys conformal invariance at the special fine-tuned value of the coupling. Counterterms for composite operators in minimal subtraction schemes do not depend on ϵ\epsilon by construction, and therefore the renormalization group equations for composite operators in physical (integer) dimensions inherit conformal symmetry. This observation can be used to restore the complete evolution kernels that take into account mixing with the operators containing total derivatives from their eigenvalues (anomalous dimensions). Using this approach we calculate the two-loop (NLO) evolution kernels for the leading twist flavor-singlet operators in the position space (light-ray operator) representation. As the main result of phenomenological relevance, in this way we are able to confirm the evolution equations of flavor-singlet generalized hadron parton distributions derived earlier by Belitsky and M\"uller using a different approach.

Keywords

Cite

@article{arxiv.1901.06172,
  title  = {Two-loop evolution equations for flavor-singlet light-ray operators},
  author = {V. M. Braun and A. N. Manashov and S. Moch and M. Strohmaier},
  journal= {arXiv preprint arXiv:1901.06172},
  year   = {2019}
}

Comments

27 pages, 4 figures

R2 v1 2026-06-23T07:15:32.382Z