A unitary model for meson-nucleon scattering

Abstract

In an effective Lagrangian model employing the K-matrix approximation we extract nucleon resonance parameters. To this end we analyze simultaneously all available data for reactions involving the final states $\pi N$, $\pi \pi N$, $\eta N$ and $K\Lambda$ in the energy range $m_N+m_{\pi }\le \sqrt{s}\le 1.9$ GeV. The background contributions are generated consistently from the relevant Feynman amplitudes, thus significantly reducing the number of free parameters.

Comments: Revised version. 60 pages, 17 figures. Two figures and a short discussion (\pi N \to \eta N, K \Lambda amplitudes) added, typos and minor errors in the citations corrected