Cloudy bag model for theS-DwaveK¯-Nsystem

The cloudy quark bag model is applied to the coupled (K¯N,Σπ,Λπ) system for S-D partial waves. Energy-dependent separable potentials are derived, as are new numerical algorithms for solving the coupled Lippmann-Schwinger equations. The parameters of the model are fit to ${\mathit{K}}^{\mathrm{-}}$p scattering and reaction cross sections, branching ratios, and mass spectra from ${\mathit{K}}^{\mathrm{-}}$p→Σπππ,Λπππ. Within the constraints of the model, the branching ratio and Σπ mass spectrum data are in conflict. The ${\mathrm{\Sigma }}_{\mathit{p}13}$(1385) and ${\mathrm{\Lambda }}_{\mathit{D}03}$(1520) resonances are found to be predominately elementary bag states with considerable dressing for the ${\mathrm{\Sigma }}_{\mathit{P}13}$. The ${\mathrm{\Lambda }}_{\mathit{S}01}$ (1405) appears as a complicated composite systems arising from two poles. The model with certain parameter sets does predict two sign changes in the real part of the K¯N scattering amplitude near threshold, but they are not quite at the correct energies to produce agreement with the sign of the strong interaction shift of kaonic hydrogen.