Σ and Ξ electromagnetic form factors in the extended vector meson dominance model

We propose a phenomenological extended vector meson dominance model for the baryon electromagnetic structure, and it is found that the current experimental data on the $\mathrm{\ensuremath{\Sigma}}$ and $\mathrm{\ensuremath{\Xi}}$ electromagnetic form factors in the timelike region can be well described. Meanwhile, we can also reproduce the ratios of the total cross sections of reactions ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{+}{\overline{\mathrm{\ensuremath{\Sigma}}}}^{\ensuremath{-}}$, ${\mathrm{\ensuremath{\Sigma}}}^{0}{\overline{\mathrm{\ensuremath{\Sigma}}}}^{0}$, and ${\mathrm{\ensuremath{\Sigma}}}^{\ensuremath{-}}{\overline{\mathrm{\ensuremath{\Sigma}}}}^{+}$, which are $9.7\ifmmode\pm\else\textpm\fi{}1.3\ensuremath{\mathbin:}3.3\ifmmode\pm\else\textpm\fi{}0.7\ensuremath{\mathbin:}1$ at center-of-mass energies from 2.3864 GeV to 3.02 GeV. We also analytically continue the expression of the form factors to spacelike region and estimate the charge radii of the $\mathrm{\ensuremath{\Sigma}}$ and $\mathrm{\ensuremath{\Xi}}$ hyperons. The obtained result of the charge radius for the ${\mathrm{\ensuremath{\Sigma}}}^{\ensuremath{-}}$ is in agreement with the experimental data.