Electromagnetic Decays of Hyperons (II)

TL;DR

This paper calculates excited hyperon masses, decay widths, and coupling constants using a chiral bag model, highlighting the small impact of meson cloud corrections and emphasizing the importance of radiative decay widths for testing quark models.

Contribution

It introduces a perturbative approach to hyperon properties within a chiral bag model, including electromagnetic and hadronic decay calculations, and discusses dispersive effects on hyperon masses.

Findings

Hadronic widths of $ ama$ and $ amb$ calculated.

Meson cloud corrections to electromagnetic widths are small.

Hyperon radiative decay widths are effective tests for quark models.

Abstract

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.