$e^{+}{e}^{-}\to {\Lambda }_c^{+}{\overline{\Lambda }}_c^{-}$ Cross Sections and the ${\Lambda }_c^{+}$ Electromagnetic Form Factors within the Extended Vector Meson Dominance Model

Within the extended vector meson dominance model, we investigate the $e^{+}{e}^{-}\to {\Lambda }_c^{+}{\overline{\Lambda }}_c^{-}$ reaction and the electromagnetic form factors of the charmed baryon ${\Lambda }_c^{+}$. The model parameters are determined by fitting them to the cross sections of the process $e^{+}{e}^{-}\to {\Lambda }_c^{+}{\overline{\Lambda }}_c^{-}$ and the magnetic form factor |G_M| of ${\Lambda }_c^{+}$. By considering four charmonium-like states, called ψ(4500), ψ(4660), ψ(4790), and ψ(4900), we can well describe the current data on the $e^{+}{e}^{-}\to {\Lambda }_c^{+}{\overline{\Lambda }}_c^{-}$ reaction from the reaction threshold up to 4.96 GeV. In addition to the total cross sections and |G_M|, the ratio |G_E/G_M| and the effective form factor |G_eff| for ${\Lambda }_c^{+}$ are also calculated, and found that these calculations are consistent with the experimental data. Within the fitted model parameters, we have also estimated the charge radius of the charmed ${\Lambda }_c^{+}$ baryon.