Theory of Eta Photo- and Electroproduction
  We analyze the available data on eta photo- and electroproduction, around W~1535 MeV, in the framework of the effective Lagrangian approach, and extract, in a nearly model-independent fashion, the electrostrong amplitude for the gamma+N--> N*(1535)--> N+eta processes. Quark model approaches are shown to be quite inadequate to explain this property at all Q^2. In particular, at high Q^2, the extracted amplitude falls much slower than the predictions of the quark model, as a function of Q^2, a situation similar to the electroexcitation and decay of Delta(1232). A QCD explanation of these observations is urgently needed. 
Nimai C. Mukhopadhyay (1), J. -F. Zhang (1) and M. Benmerrouche (1 and   2) ((1) RPI, (2) SAL)