In this presentation, we report our recent studies on the photoproduction off the proton target, using the tree-level Born approximation, via the effective Lagrangian approach. In addition, we include the nine (three- or four-star confirmed) nucleon resonances below the threshold MeV, to interpret the discrepancy between the experiment and previous theoretical studies, in the vicinity of the threshold region. From the numerical studies, we observe that the and play an important role for the cross-section enhancement near the . It also turns out that, in order to reproduce the data, we have the vector coupling constants and .

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