The neutron anomaly in the gamma N --> eta N cross section through the   looking glass of the flavour SU(3) symmetry
  We study the implications of the flavour SU(3) symmetry for various interpretations of the neutron anomaly in the $\gamma N\to\eta N$ cross section. We show that the explanation of the neutron anomaly due to interference of known N(1535) and N(1650) resonances implies that N(1650) resonance should have a huge coupling to $\phi$-meson -- at least 5 times larger than the corresponding $\rho^0$ coupling. In terms of quark degrees of freedom this means that the well-known N(1650) resonance must be a "cryptoexotic pentaquark"-- its wave function should contain predominantly an $s\bar s$ component.   It turns out that the "conventional" interpretation of the neutron anomaly by the interference of known resonances metamorphoses into unconventional physics picture of N(1650). 
T. Boika, V. Kuznetsov, M.V. Polyakov
nucl-th hep-ex hep-ph nucl-ex