Subleading power corrections to the pion-photon transition form factor in QCD

Author(s)
Yu-Ming Wang, Yue-Long Shen
Abstract

We reconsider QCD factorization for the leading power contribution to the gamma*gamma -> pi(0) form factor F-gamma*gamma -> pi 0 (Q(2)) at one loop using the evanescent operator approach, and demonstrate the equivalence of the resulting factorization formulae derived with distinct prescriptions of gamma(5) in dimensional regularization. Applying the light-cone QCD sum rules (LCSRs) with photon distribution amplitudes (DAs) we further compute the subleading power contribution to the pion-photon form factor induced by the "hadronic" component of the real photon at the next-to-leading-order in O(alpha(s)), with both naive dimensional regularization and 't Hooft-Veltman schemes of gamma(5). Confronting our theoretical predictions of F-gamma*gamma -> pi 0 (Q(2)) with the experimental measurements from the BaBar and the Belle Collaborations implies that a reasonable agreement can be achieved without introducing an "exotic" end-point behaviour for the twist-2 pion DA.

Organisation(s)
Particle Physics
External organisation(s)
Nankai University, Ocean University of China
Journal
Journal of High Energy Physics
No. of pages
38
ISSN
1029-8479
DOI
https://doi.org/10.1007/JHEP12(2017)037
Publication date
12-2017
Peer reviewed
Yes
Austrian Fields of Science 2012
103012 High energy physics
Keywords
Portal url
https://ucris.univie.ac.at/portal/en/publications/subleading-power-corrections-to-the-pionphoton-transition-form-factor-in-qcd(c94fb478-936b-4111-b714-bdd3d64c583f).html