We report on the measurement of the beam asymmetry $\Sigma$ for the reactions $\vec{ \gamma}p\rightarrow p\eta$ and $\vec{ \gamma}p \rightarrow p\eta^{ \prime}$ from the GlueX experiment, using an 8.2--8.8 GeV linearly polarized tagged photon beam incident on a liquid hydrogen target in Hall D at Jefferson Lab. These measurements are made as a function of momentum transfer $-t$, with significantly higher statistical precision than our earlier $\eta$ measurements, and are the first measurements of $\eta^{ \prime}$ in this energy range. We compare the results to theoretical predictions based on $t$--channel quasi-particle exchange. We also compare the ratio of $\Sigma_{ \eta}$ to $\Sigma_{ \eta^{ \prime}}$ to these models, as this ratio is predicted to be sensitive to the amount of $s\bar{ s}$ exchange in the production. We find that photoproduction of both $\eta$ and $\eta^{ \prime}$ is dominated by natural parity exchange with little dependence on $-t$.
Categories: nucl-ex hep-ex