We show that two almost degenerate poles near the π Δ threshold and the next higher mass
pole in the P 11 partial wave of π N scattering evolve from a single bare state through its
coupling with π N, η N, and π π N reaction channels. This finding provides new information
on understanding the dynamical origins of the Roper N*(1440) and N*(1710) resonances
listed by Particle Data Group. Our results for the resonance poles in other π N partial waves
are also presented.

Disentangling the Dynamical Origin of P11 Nucleon Resonances | CiNii Research …
Disentangling the Dynamical Origin of P11 Nucleon Resonances … タイトル Disentangling
the Dynamical Origin of P11 Nucleon Resonances …