Unitary model for meson-nucleon scattering

We extract nucleon resonance parameters from an effective Lagrangian model employing the K-matrix approximation. To this end we analyze simultaneously all available data for reactions involving the final states πN, ππN, ηN, and KΛ in the energy range mN+m_π<~√s<~1.9 GeV. The background contributions are generated consistently from the relevant Feynman amplitudes, which significantly reduces the number of free parameters. The sensitivity of the parameters upon the πN--partial-wave analysis and the details of the Lagrangians and form factors used are discussed.