The Electromagnetic Form Factors of Σ and Σ⁰ → Λ Transition in the Timelike Region

Abstract We investigate the $e^{+}{e}^{-}\to \Sigma \overline{\Sigma }$ and $e^{+}{e}^{-}\to \Lambda {\overline{\Sigma }}^0$ reactions within the extended vector meson dominance model. In addition to the ground state mesons ρ and ω, we consider the contributions of the excited states ρ(3D), ω(3D), ϕ(3D), and ρ(2850). It is found that the current experimental data on the Σ electromagnetic form factors in timelike region can be well reproduced. The ϕ(3D) resonance is essential to the near threshold enhancement of the cross-section for the $e^{+}{e}^{-}\to \Sigma \overline{\Sigma }$ reaction. Furthermore, in the $e^{+}{e}^{-}\to \Lambda {\overline{\Sigma }}^0$ reaction, the ρ(3D) is important to get a good fit for the experimental results.