Pion-photon transition distribution amplitudes in the spectral quark model

The vector and axial pion-photon transition distribution amplitudes are analyzed in the spectral quark model. We proceed by the evaluation of double distributions through the use of a manifestly covariant calculation based on the α representation of propagators. As a result polynomiality is incorporated and calculations become rather simple. Explicit formulas, holding at the low-energy quark-model scale, are obtained. The corresponding form factors for the anomalous decay π0→γγ* and the radiative pion decays π±→l±νlγ are also evaluated and confronted with the data