Dynamical coupled-channel model of kaon-hyperon interactions

The πN → KY and KY → KY reactions are studied using a dynamical coupled-channel model of meson-baryon interactions at energies where the baryon resonances are strongly excited. The channels included are: πN , KΛ, and KΣ. The resonances considered are: N [S11(1650), P11(1710), P13(1720), D13(1700)]; ∆ ∗ [S31(1900), P31(1910), P33(1920)]; Λ ∗ [S01(1670), P01(1810)] Σ [P11(1660), D13(1670)]; and K (892). The basic non-resonant πN → KY and KY → KY transition potentials are derived from effective Lagrangians using a unitary transformation method. The dynamical coupled-channel equations are simplified by parametrizing the πN → πN amplitudes in terms of empirical πN partial-wave amplitudes and a phenomenological off-shell function. Two models have been constructed. Model A is built by fixing all coupling constants and resonance parameters using SU(3) symmetry, the Particle Data Group values, and results from a constituent quark model. Model B is obtained by allowing most of the parameters to vary around the values of model A in fitting the data. Good fits to the available data for πp → KΛ, KΣ have been achieved. The investigated kinematics region in the center-of-mass frame goes from threshold to 2.5 GeV. The constructed models can be imbedded into associated dynamical coupled-channel studies of kaon photoand electro-production reactions. PACS numbers: 11.80.-m, 11.80Gw, 13.75.-n, 24.10.Eq