The form factors for the photon to pseudoscalar meson transitions - an update

Understand

The form factors for the transitions pi-photon, eta-photon, eta'-photon and etac-photon are analyzed within the modified perturbative approach in which quark transverse degrees of freedom are retained.

• The results for the form factors are compared to experiment in detail.
• As compared to previous calculations within the same approach only little modifications of the meson distribution amplitudes are required in general in order to achieve agreement with experiment.
• Only for the pi-photon form factor a strong contribution from the second Gegenbauer term is found.