Constraints on distribution amplitudes of the η and η′ mesons in the light of new experimental results

Abstract

Constraints on the distribution amplitudes of the SU _f (3) singlet η ₁ and octet η ₈ states are obtained from a comparison of the theoretical predictions for the η γ and η′γ electromagnetic transition form factors with experimental data of the CLEO and BaBar Collaborations. In calculations of the form factors F _η(η′)γ(Q ²) the power-suppressed corrections arising from the end-point integration regions x→0,1 are taken into account by employing the infrared renormalon approach. It is demonstrated that the power-suppressed corrections allow one to describe the data on the η γ and η′γ transitions within a framework of the SU _f (3) octet–singlet basis using one mixing angle for both the physical states and decay constants.