Gluon content of the η and η′ mesons and the ηγ, η′γ electromagnetic transition form factors -: art. no. 054020

We compute power-suppressed corrections to the etagamma and eta(')gamma transition form factors Q(2)F(eta(eta)('))gamma(Q(2)) arising from the end point regions x-->0,1 by employing the infrared-renormalon approach. The contribution to the form factors from the quark and gluon content of the eta,eta(') mesons is taken into account using for the eta-eta(') mixing the SUf(3) singlet eta(1) and octet eta(8) basis. The theoretical predictions obtained this way are compared with the corresponding CLEO data and restrictions on the input parameters (Gegenbauer coefficients) B-2(q)(eta(1)), B-2(g)(eta(1)), and B-2(q)(eta(8)) in the distribution amplitudes for the eta(1),eta(8) states with one nonasymptotic term are deduced. Comparison is made with the results from QCD perturbation theory.