Chiral Dynamics and the Low Energy Kaon-Nucleon Interaction

Abstract

We examine the meson-baryon interaction in the strangeness S=-1 sector using an effective chiral Lagrangian. Potentials are derived from this Lagrangian and used in a coupled-channel calculation of the low energy observables. The potentials are constructed such that in the Born approximation the s-wave scattering amplitude is the same as that given by the effective chiral Lagrangian, up to order $q^2$. Comparison is made with the available low energy hadronic data of the coupled $K^{-}p,\Sigma \pi ,\Lambda \pi$ system, which includes the $\Lambda (1405)$ resonance, $K^{-}p$ elastic and inelastic scattering, and the threshold branching ratios of the $K^{-}p$ decay. Good fits to the experimental data and estimates of previously unknown Lagrangian parameters are obtained.

Comments: 20 pages, 10 postscript figures, uses revtex, e-mail addresses: Norbert.Kaiser@physik.tu-muenchen.de, Peter.Siegel@physik.tu-muenchen.de, Wolfram.Weise@physik.tu-muenchen.de