Self-Consistent Three-Body Calculation of Pion-Nucleon Scattering

Abstract

Using an off-energy-shell static theory which treats three-particle unitarity exactly, but neglects left-hand cuts, we describe rather well the low-energy $P$-wave $N\pi$ system. We obtain a well-satisfied "bootstrap" requirement in the (3,3) channel and a possible explanation for the Roper resonance in the (1,1) channel.