Parameterization dependence of T matrix poles and eigenphases from a fit   to piN elastic scattering data
  We compare fits to piN elastic scattering data, based on a Chew-Mandelstam K-matrix formalism. Resonances, characterized by T-matrix poles, are compared in fits generated with and without explicit Chew-Mandelstam K-matrix poles. Diagonalization of the S matrix yields the eigenphase representation. While the eigenphases can vary significantly for the different parameterizations, the locations of most T-matrix poles are relatively stable. 
R. L. Workman (GWU), R. A. Arndt (GWU), W. J. Briscoe (GWU), M. W.   Paris (LANL), I. I. Strakovsky (GWU)
hep-ph hep-ex nucl-ex nucl-th