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) ] ; Δ^* [ S₃₁ (1900), P₃₁ (1910), P₃₃ (1920) ] ; Λ^* [ S₀₁ (1670), P₀₁ (1810) ] Σ^* [ P₁₁ (1660), D₁₃ (1670) ] ; and K^* (892) . The basic nonresonant 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 π^- p→ K⁰ Λ, K⁰ Σ⁰ 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 photo- and electroproduction reactions.