Wide-angle photoproduction of the η′ -meson and its gluon content

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