Pole structure from energy-dependent and single-energy fits to $\pi N$ elastic scattering data

Abstract

The pole structure of the current GW/SAID partial-wave analysis of elastic $\pi N$ scattering and $\eta N$ production data is studied. Pole positions and residues are extracted from both the energy-dependent and single-energy fits, using two different methods. For the energy-dependent fits, both contour integration and a Laurent+Pietarinen approach are used. In the case of single-energy fits, the Laurent+Pietarinen approach is used. Errors are estimated and the two sets of results are compared to other recent and older fits to data.

Comments: 12 pages,5 tables,2 figures. arXiv admin note: substantial text overlap with arXiv:1401.1947, arXiv:1404.1544