Lifetime of theΣ0

Abstract

A dispersion-theoretic calculation of the lifetime of the ${\ensuremath{\Sigma}}^{0}$ is carried out along lines suggested by previous treatments of the nucleon electromagnetic form factors. In terms of the coupling constants of the $\ensuremath{\Sigma}$, $\ensuremath{\Lambda}$, and $N$ baryons to the pion (${g}_{\ensuremath{\Lambda}}, {g}_{\ensuremath{\Sigma}}, \mathrm{and} g$), the ${\ensuremath{\Sigma}}^{0}$ lifetime is predicted to be $\ensuremath{\tau}={(\frac{{g}_{\ensuremath{\Sigma}}{g}_{\ensuremath{\Lambda}}}{{g}^{2}})}^{\ensuremath{-}2}\ifmmode\times\else\texttimes\fi{}1.1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}19}$ sec, irrespective of the relative ($\ensuremath{\Lambda}, \ensuremath{\Sigma}$) parity, the validity of this expression depending on the dominance of the two-pion resonating state contribution to the ${\ensuremath{\Sigma}}^{0}\ensuremath{\rightarrow}\ensuremath{\Lambda}+\ensuremath{\gamma}$ transition magnetic moment.