Chiral Dynamics for High-Spin Baryons and an Application to Double-Pion Photoproduction

Abstract

An $\mathrm{SU}\left(2\right)\mathrm{}\times \mathrm{SU}\left(2\right)\mathrm{}$ chiral-dynamical Lagrangian for baryons of arbitrary spin and isospin is discussed. Cross sections for low-energy double-pion photoproduction from a nucleon are calculated by assuming that the nucleon and one final pion form an isobar $\Delta \left(1236\mathrm{} \mathrm{MeV}\right)$. The results are compared with those obtained by the soft-pion dispersion-relation approach. It is shown that the static-nucleon model gives satisfactory total cross sections but is inadequate for angular-distribution differential cross sections. Our theoretical predictions are consistent with experiment.