The $\Sigma$ and $\Xi$ electromagnetic form factors in the extended vector meson dominance model

Abstract

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 $\Sigma$ and $\Xi$ electromagnetic form factors in the time-like region can be well described. Meanwhile, we can also reproduce the ratios of the total cross sections of reactions $e^{+}{e}^{-}\to {\Sigma }^{+}{\bar{\Sigma }}^{-}$, ${\Sigma }^0{\bar{\Sigma }}^0$, and ${\Sigma }^{-}{\bar{\Sigma }}^{+}$, which are $9.7\pm 1.3:3.3\pm 0.7:1$ at center-of-mass energies from $2.3864$ to $3.02$ GeV. We also analytically continue the expression of the form factors to space-like region and estimate the charge radii of the $\Sigma$ and $\Xi$ hyperons. The result for the ${\Sigma }^{-}$ is in agreement with the experimental date.

Comments: 7 pages, 5 figures. Typos are fixed