Wide-angle photoproduction of the ǡ-meson and its gluon content

We investigate wide-angle photoproduction of the eta'-meson within the handbag approach to twist-3 accuracy. It turns out that, due to the gluon content of the eta', this process is dominated by twist 2 in contrast with pion and eta photoproduction. Using the presently available information on the twist-2 and twist-3 distribution amplitudes and on the eta - eta' mixing, we provide prediction for the eta' cross section and helicity correlations. It is argued that eta' photoproduction is well suited to improve our knowledge of the two-gluon distribution amplitude.