K+-Nucleon Scattering in an Effective Chiral Lagrangian Model

The $S$-wave $K^{+}$-nucleon scattering lengths are calculated in a phenomenological chiral model containing baryons and pseudoscalar mesons. Good agreement with experiment is found, in contrast to the usual current-algebra results which correspond to unphysical limits of our expressions. The sensitivity of the calculation to various modifications of the Langrangian is also discussed. In particular, the scattering lengths are observed to be rather dependent on the way $\mathrm{SU}\left(3\right)\mathrm{}$ symmetry breaking is introduced into the model.