ИСТИНА

We investigate the form factors for pseudoscalar-meson-photon transitions by means of dispersive QCD sum rules and demonstrate that most of the measurements done so far (in particular, those by BaBar for η, η′, and ηc and those by Belle for π0) are, on the one hand, compatible with each other and with the saturation required by factorization theorems obtained from perturbative QCD and, on the other hand, give a hint that saturation is effective already at relatively low momentum transfers Q2; this hypothesis is supported by experimental data for the charged-pion elastic form factor available in the range $Q^2\approx2-4\;\{GeV}^2.$ The only exception are the BaBar results for the π0γ transition form factor, which do not fit into such picture. We point out that results expected from SHMS at JLab on the pion elastic form factor in the region $Q^2\approx5-8\;\{GeV}^2$ will provide the ultimate test of saturation and factorization and strongly impact our general view of the form factors up to infinitely large Q2.