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

Abstract

Based on the recently measurements of the e + e − → Σ + Σ− and e + e − → Σ − Σ+ processes by BESIII collaboration, the electromagnetic form factors of the hyperon Σ + and Σ − in the timelike region are investigated by using the vector meson dominance model, where the contributions from the ρ, ω, and φ mesons are taken into account. The model parameters are determined with the BESIII experimental data on the timelike effective form factors |G eff | of Σ + and Σ − baryons for center-of-mass energy from 2.3864 to 3.02 GeV. It is found that we can provide quantitative descriptions of available data as few as one adjustable model parameter. Then, we analytically continue the electromagnetic form factors to spacelike region and evaluate the spacelike form factors of hyperons Σ + and Σ − . The obtained electromagnetic form factors of the Σ + and Σ − baryons are comparable with other model calculations.

The electromagnetic form factors of $Λ_c$ hyperon in the vector meson dominance model

“…Previously, the VMD model have been widely used to study the EMFFs of the nucleon and the Λ hyperon, showing that it has the advantage to well describe the experimental data in the space-like and time-like region [15,27,[43][44][45][46]. Very recently, it has also been applied to investigate the EMFFs for Σ + and Σ − [25]. Encouraged by its success, we extend the model to study the EMFFs of the Λ c hyperon.…”

“…In the last two decades, the EMFFs of hyperons (i.e., Λ, Σ, Ξ) in the time-like region have also been investigated. Particularly, the enhancement of the cross sections in reactions e + e − → Y Ȳ near threshold were measured and analyzed [20][21][22][23][24][25]. It is found that the vector mesons and their resonances, as the intermediate states of the reaction, play important roles in these processes.…”

Electromagnetic form factors of the $Ω^-$ baryon in the spacelike and timelike regions

“…The first theoretical estimates of the e + e − → B B cross sections and hyperon effective form factor, in the timelike region, were based on vector meson dominance (VMD) models [69,70]. More recently, with the emergence of accurate data for a variety of hyperons, new models have been proposed [6,[71][72][73][74], including improved VMD models [75][76][77][78][79][80]. Most of these studies focus on the Λ and Σ systems.…”