Photoproduction of η mesons off protons for Eγ ≤ 1.15 GeV

eta mesons emitted from the photoproduction off protons were measured for 0.70 <= E-gamma <= 1.15 GeV. The gamma p ->eta p reaction process was separated from the pi eta p final state by the momentum difference of eta mesons for E-gamma >= 930 MeV. The angular distributions obtained and the excitation function of the gamma p ->eta p reaction are essentially in good agreement with previously reported ones and are well explained by eta-MAID calculations. For the gamma p ->pi eta N reaction, the cross section increases monotonically with increasing photon energy, and it almost reaches the value of the gamma p ->eta p reaction at E(gamma similar to)1.15 GeV. The momentum distributions are compared with kinematic calculations. It is suggested that the sequential decay process through the P-33(1232) resonance [gamma p ->eta P-33(1232)->pi eta N] contributes to the gamma p ->pi eta N reaction, in addition to the sequential process gamma p ->pi S-11(1535)->pi eta N and/or pi and eta emissions without intermediate nucleon resonances.