Medium-energyNππdynamics. I

Abstract

New formal apparatus is developed for the dynamics of the $N\ensuremath{\pi}\ensuremath{\pi}$ system. The ingredients are the isobar expansion with Bose symmetry, and subenergy unitarity and analyticity. The family of isobar amplitudes considered is substantial in number and realistic for a medium-energy treatment. Dispersion relations are written and the Pasquier inversion procedure is employed, leading to a set of coupled single-variable integral equations. The resulting linear system is suitable for investigating three-body dynamics and for carrying out phenomenological analyses.