English

QCD$\times$QED evolution of TMDs

High Energy Physics - Phenomenology 2018-11-21 v2 High Energy Physics - Theory

Abstract

We consider for the first time the QED corrections to the evolution of (un)polarized quark and gluon transverse-momentum-dependent distribution and fragmentation functions (TMDs in general). By extending their operator definition to QCD×\timesQED, we provide the mixed new anomalous dimensions up to O(αsα){\cal O}(\alpha_s\alpha) and the pure QED ones up to O(α2){\cal O}(\alpha^2). These new corrections are universal for all TMDs up to the flavor of the considered parton, i.e., the full flavor universality of TMD evolution found in pure QCD is broken in QCD×\timesQED by the presence of the electric charge. In addition, we provide the leading-order QED corrections to the matching coefficients of the unpolarized quark TMD parton distribution function onto its integrated counterparts at O(αs0α){\cal O}(\alpha_s^0\alpha).

Keywords

Cite

@article{arxiv.1810.02297,
  title  = {QCD$\times$QED evolution of TMDs},
  author = {Alessandro Bacchetta and Miguel G. Echevarria},
  journal= {arXiv preprint arXiv:1810.02297},
  year   = {2018}
}

Comments

9 pages, 3 figures. v2: minor corrections, accepted for publication in Phys. Lett. B

R2 v1 2026-06-23T04:28:41.092Z