The $\gamma^\ast\to \eta\gamma$ and $\gamma^\ast\to \eta'\gamma$ form factors to NNLO accuracy in perturbative QCD

V. M. Braun; K. G. Chetyrkin; A. N. Manashov

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arXiv · 2510.15643

The $\gamma^\ast\to \eta\gamma$ and $\gamma^\ast\to \eta'\gamma$ form factors to NNLO accuracy in perturbative QCD

V. M. Braun·K. G. Chetyrkin·A. N. Manashov

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Abstract

We use conformal symmetry to calculate the NNLO anomalous dimension matrix (three loops) for flavor-singlet axial-vector QCD operators for spin $N \le 8$ from a set of gauge-invariant two-point correlation functions. Combining this result with the recent calculation of the two-loop coefficient functions, we carry out the calculation of the $\gamma\gamma^\ast\to \eta$ and $\gamma\gamma^\ast\to \eta'$ form factors at large momentum transfers to the NNLO accuracy in perturbative QCD.

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V. M. Braun, K. G. Chetyrkin, A. N. Manashov. 2025-10-17. The $\gamma^\ast\to \eta\gamma$ and $\gamma^\ast\to \eta'\gamma$ form factors to NNLO accuracy in perturbative QCD. https://arxiv.org/abs/2510.15643

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