Quasi-free photoproduction of eta-mesons of the neutron
  Quasi-free photoproduction of eta-mesons off nucleons bound in the deuteron has been measured with the CBELSA/TAPS detector for incident photon energies up to 2.5 GeV at the Bonn ELSA accelerator. The eta-mesons have been detected in coincidence with recoil protons and recoil neutrons, which allows a detailed comparison of the quasi-free n(gamma,eta)n and p(gamma,eta)p reactions. The excitation function for eta-production off the neutron shows a pronounced bump-like structure at W=1.68 GeV (E_g ~ 1 GeV), which is absent for the proton. 
I. Jaegle, T. Mertens, A.V. Anisovich, J.C.S. Bacelar, B. Bantes, O.   Bartholomy, D. Bayadilov, R. Beck, Y.A. Beloglazov, R...