Masses and widths ofNand Δ resonances

A simple approximation is derived to relate the complex pole in a resonant partial-wave T-matrix amplitude to the conventional Breit-Wigner parameters that describe the scattering resonance. The approximation is tested by using well-established resonance parameters for the Δ(1232)3/$2^{+}$. This new result facilitates a comparison of both Breit-Wigner parameters and pole positions for 17 resonances described by four major analyses of πN scattering.