Study of the electromagnetic form factors of the nucleons in the timelike region

The electromagnetic form factors G_E and G_M of the proton and neutron in the timelike region are extracted in a study of the processes e⁺e⁻ → $\overline{p}p$ \( \overline{p}p \) and e⁺e⁻ → $\overline{n}n$ \( \overline{n}n \) . The reaction amplitude is evaluated within the distorted wave Born approximation, with the interaction of the antinucleon-nucleon $\left(\overline{N}N\right)$ \( \left(\overline{N}N\right) \) pair taken into account. The latter is constructed within SU(3) chiral effective field theory up to next-to-leading order. An excellent description of the e⁺e⁻ → $\overline{N}N$ \( \overline{N}N \) data in the energy region from the $\overline{N}N$ \( \overline{N}N \) threshold up to center-of-mass energies E_cm = 2.2 GeV is achieved. Results for the electromagnetic form factors G_E, G_M, G_E/G_M, and the subtracted effective form factors, G_osc, are provided. These can be helpful for further studies of the properties of the nucleons.