We report results on the π-γ transition form factor obtained within the hard scattering approach including transverse momentum effects and Sudakov corrections. The results clearly favor distribution amplitudes close to the asymptotic form, ∼ x 1 x 2 , and disfavor distribution amplitudes which are strongly concentrated in the end-point regions. This observation is backed by information on the elastic form factor of the pion and on its valence quark distribution function. Applications of our approach to the η-γ and η ′ -γ transition form factors are discussed as well. Combining the form factor data with the twophoton decay widths, we determine the η and the η ′ decay constants and the η-η ′ mixing angle.

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