Electromagnetic Decays of Hyperons (II)

Excited negative parity hyperon masses are calculated in a chiral bag model in which the pion and the kaon fields are treated as perturbations. We also calculate the hadronic widths of $\lama$ and $\lamb$ as well as the coupling constants of the lightest $I=0$ excited hyperon to the meson-baryon channels, and discuss how the dispersive effects of the hadronic meson-baryon decay channels affect the excited hyperon masses. Meson cloud corrections to the electromagnetic decay widths of the two lightest excited hyperons into ground states $\lamz$ and $\sigz$ are calculated within the same model and are found to be small. Our results strengthen the argument that predictions of these hyperon radiative decay widths provide an excellent test for various quark models of hadrons.