  The photoproduction reaction of $\gamma p \to \eta^\prime p$ is investigated
based on an effective Lagrangian approach in the tree-level approximation, with
the purpose being to understand the reaction mechanisms and to extract the
resonance contents and the associated resonance parameters in this reaction.
Apart from the $t$-channel $\rho$ and $\omega$ exchanges, $s$- and $u$-channel
nucleon exchanges, and generalized contact term, the exchanges of a minimum
number of nucleon resonances in the $s$ channel are taken into account in
constructing the reaction amplitudes to describe the experimental data. It is
found that a satisfactory description of the available data on both
differential cross sections and photon beam asymmetries can be obtained by
including in the $s$ channel the exchanges of the $N(1875)3/2^-$ and
$N(2040)3/2^+$ resonances. The reaction mechanisms of $\gamma p \to \eta^\prime
p$ are discussed and a prediction for the target nucleon asymmetries is
presented.
