Chiral SU(3) dynamics with coupled channels: inclusion of p-wave multipoles Original Research Article

We extend our recent non-perturbative chiral SU(3) coupled channel approach to pion- and photon-induced η- and K-meson production off protons by including all strong and electromagnetic p-wave multipoles. We identify the p-wave amplitudes of the next-to-leading order SU(3) chiral meson–baryon Lagrangian with a coupled channel potential which is iterated to infinite orders in a separable Lippmann–Schwinger equation. Our approach to η- and K-photoproduction introduces no additional free parameters. By adjusting a few finite range parameters and the unknown parameters in the Lagrangian, we are able to simultaneously describe a very large amount of low-energy data. These include the total and differential cross sections of the π-induced reactions π−p→ηn,K0Λ,K0Σ0,K+Σ− and π+p→K+Σ+ as well as those of photoproduction γp→ηp,K+Λ,K+Σ0,K0Σ+. The polarization observables measured in η- and K-photoproduction are particularly sensitive to interference terms between the s- and p-wave multipoles. The total cross section data are remarkably well reproduced in all channels. There remain, however, some open questions concerning details of angular distributions and polarization observables.