Poles of the. pi. N P sub 11 partial-wave amplitude

We have carried out fits to the energy dependence of the {ital P}{sub 11} partial-wave amplitude as obtained in two different single-energy analyses of {pi}-{ital N} scattering data. Data on inelastic cross sections were also used. The fits used an analytic approximation to the coupled-channel amplitudes suggested by the Dyson equations. From each set of partial-wave data, two resonances were obtained, at roughly 1470 and 1700 MeV. Each of these resonances is associated with a cluster of poles on the Riemann surface.