Published: 2010
Total Pages: 7
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We discuss the relevance of a dedicated measurement of exclusive production of a pair of neutral pions in a hard [gamma]*[gamma] scattering at small momentum transfer. In this case, the virtuality of one photon provides us with a hard scale in the process, enabling us to perform a QCD calculation of this reaction rate using the concept of Transition Distribution Amplitudes (TDA). Those are related by sum rules to the pion axial form factor F{sub A}{sup [pi]} and, as a direct consequence, a cross-section measurement of this process at intense beam electron-positron colliders such as CLEO, KEK-B and PEP-II, or Super-B would provide us with a unique measurement of the neutral pion axial form factor F{sub A}{sup [pi]0} at small scale. We believe that our models for the photon to meson transition distribution amplitudes are sufficiently constrained to give reasonable orders of magnitude for the estimated cross sections. Cross sections are large enough for quantitative studies to be performed at high luminosity ee− colliders. After verifying the scaling and the [phi] independence of the cross section, one should be able to measure these new hadronic matrix elements, and thus open a new gate to the understanding of the hadronic structure. In particular, we argued here that the study of [gamma]*[gamma] 2![pi]°{pi}° in the TDA regime could provide with a unique experimental measurement of the {pi}° axial form factor.