Abstract:
We reconsider QCD factorization for the leading power contribution to the pion-photon form factor at one loop using the evanescent operator approach, and demonstrate the equivalence of the resulting factorization formulae derived with distinct prescriptions of γ5 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(αs), with both naive dimensional regularization and 't Hooft-Veltman schemes of γ5. Confronting our theoretical predictions of Fγ∗γ→π0(Q2)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.