Primakoff effect in $ \eta$ -photoproduction off protons

We analyse data on forward h \eta -meson photoproduction off a proton target and extract the h \eta ? \rightarrow g \gamma g \gamma decay width utilizing the Primakoff effect. The hadronic amplitude that enters into our analysis is strongly constrained because it is fixed from a global fit to available g \gamma p ? \rightarrow p h \eta data for differential cross-sections and polarizations. We compare our results with present information on the two-photon h \eta -decay from the literature. We provide predictions for future PrimEx experiments at Jefferson Laboratory in order to motivate further studies.