First Results on η-PHOTOPRODUCTION on the Neutron from Graal

In this talk, I present preliminary results of the recent exclusive experiment devoted to η-photoproduction on the neutron using a deuteron target. The ratio of γn → ηn/γp → ηp quasi-free differential cross sections has been measured at 120, 140, and 160° from threshold up to 1.1 GeV. In the region of the S₁₁(1535) resonance, this ratio is nearly constant. Above 1 GeV, a sharp rise has been observed.