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arXiv · 1109.2718

Pion-photon transition form factor. Living on the QCD frontier

N. G. Stefanis
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Abstract

An analysis of all available data (CELLO, CLEO, \babar) in the range $[1\div 40]$ GeV$^2$ for the pion-photon transition form factor in terms of light-cone sum rules with next-to-leading-order accuracy is discussed, including twist-four contributions and next-to-next-to-leading order and twist-six corrections---the latter two via uncertainties. The antithetic trend between the \babar data for the $\gamma^*\gamma\pi^0$ and those for the $\gamma^*\gamma\eta(\eta')$ transition is pointed out, emphasizing the underlying antagonistic mechanisms: endpoint enhancement for the first and endpoint-suppression for the second---each associated with pseudoscalar meson distribution amplitudes with distinct endpoint characteristics.

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N. G. Stefanis. 2011-09-13. Pion-photon transition form factor. Living on the QCD frontier. https://doi.org/10.1007/s00601-011-0257-2

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