Chiral symmetry and the near-threshold pion-induced 2π production on the nucleon: II. Relativistic corrections and ππ initial- and final-state interactions☆

Abstract Some extensions of a model for the π N → ππ N reaction, presented in a preceding paper, are outlined: the leading relativistic corrections to the static treatment of the baryons are derived and the main features of the ππ interaction in the initial and final state are included via σ- and ϱ-meson exchange. Besides a detailed comparison with the total cross section, the discussion focuses on the sensitivity of exclusive ππ angular distributions on relativistic and initial- and final-state corrections.