Electromagnetic form factors of $\Sigma^{+}$ and $\Sigma^{-}$ in the vector meson dominance model

TL;DR

This paper models the electromagnetic form factors of the hyperons Sigma+ and Sigma- in the timelike region using vector meson dominance, fitting parameters to recent experimental data and analytically continuing to the spacelike region.

Contribution

It introduces a VMD-based model for hyperon form factors, fitted to BESIII data, and extends the analysis to the spacelike region for the first time.

Findings

Form factors are consistent with other models.

Model parameters fitted to BESIII data.

Spacelike form factors are analytically continued.

Abstract

Based on the recently measurements of the $e^{+} e^{-} \to \Sigma^{+} \bar{\Sigma}^{-}$ and $e^{+} e^{-} \to \Sigma^{-} \bar{\Sigma}^{+}$ processes, the electromagnetic form factors of the hyperon $\Sigma^+$ and $\Sigma^-$ in the timelike region are investigate by using the vector meson dominance model. We have included the contributions from the $\rho$, $\omega$ and $\phi$ mesons. The model parameters are determined with the BESIII experimental data on the timelike effective form factors $|G_{\rm eff}|$ of $\Sigma^{+}$ and ${\Sigma}^{-}$ for center-of-mass energy from 2.3864 to 3.02 GeV. Then, we analytically continue the electromagnetic form factors to spacelike region and evaluate the spacelike form factors of $\Sigma^+$ and $\Sigma^-$. The obtained electromagnetic form factors of the $\Sigma^+$ and $\Sigma^-$ baryons are comparable with other model calculations.