Disentangling the Dynamical Origin of P11 Nucleon Resonances

Abstract

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.