e+e−→Λc+Λ¯c− Cross Sections and the Λc+ Electromagnetic Form Factors within the Extended Vector Meson Dominance Model

Abstract

Within the extended vector meson dominance model, we investigate the e + e − → Λ c + Λ ¯ c − reaction and the electromagnetic form factors of the charmed baryon Λ c + . The model parameters are determined by fitting them to the cross sections of the process e + e − → Λ c + Λ ¯ c − and the magnetic form factor |G M| of Λ 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 − → Λ c + Λ ¯ 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 Λ 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 Λ c + baryon.