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New data for the differential cross sections, polarization observables $T$,$F$, and $E$ in the reaction of $\eta$ photoproduction on proton from thethreshold up to a center-of-mass energy of W=1.9 GeV are presented. The datawere obtained with the Crystal-Ball/TAPS detector setup at the Glasgow taggedphoton facility of the Mainz Microtron MAMI. The polarization measurements weremade using a frozen-spin butanol target and circularly polarized photon beam.The results are compared to existing experimental data and different PWApredictions. The data solve a long-standing problem related the angulardependence of older $T$ data close to threshold. The unexpected relative phasemotion between $s$- and $d$-wave amplitudes required by the old data is notconfirmed. At higher energies, all model predictions fail to reproduce the newpolarization data indicating a significant impact on our understanding of theunderlying dynamics of $\eta$ meson photoproduction. Furthermore, we present afit of the new data and existing data from GRAAL for $\Sigma$ asymmetry basedon an expansion in terms of associated Legendre polynomials. A Legendredecomposition shows the sensitivity to small partial-wave contributions. Thesensitivity of the Legendre coefficients to the nucleon resonance parameters isshown using the $\eta$MAID isobar model.

Experimental study of $\eta$ meson photoproduction reaction at MAMI