Parameterization dependence of T matrix poles and eigenphases from a fit to piN elastic scattering data

TL;DR

This paper compares different parameterizations of piN elastic scattering data using a Chew-Mandelstam K-matrix approach, analyzing the stability of T-matrix poles and eigenphases across models.

Contribution

It demonstrates that T-matrix pole locations are stable despite variations in eigenphase parameterizations, highlighting robustness in resonance identification.

Findings

T-matrix poles are relatively stable across different fits.

Eigenphases can vary significantly with parameterization.

Resonance pole positions are robust indicators.

Abstract

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.