Presence of Extra P11 Resonances in Zagreb Analysis Since 1995
  The partial wave T-matrices for the pi N, eta N and pi2 N channels have been obtained within the framework of the coupled channel model using the pi N elastic and pi N --> eta N data base as input. It has been shown that for the P11 partial wave an equally good representation of the experimental data (namely the T(pi N,pi N) and T(pi N,eta N) T-matrices) can be obtained using either three, or four poles for the Green function propagator. However, the three Green function pole solution is not acceptable due to the structure of the extracted resonances. The two out of four P11 resonances, those lying in the energy range 1700 MeV < MR < 1800 MeV, are poorly determined, but they seem to be strongly inelastic. The inclusion of other inelastic channels is needed to determine masses and widths of missing resonances with greater precision. 
S. Ceci, A. Svarc, B. Zauner