Nucleon polarization in the process e+e−→NN¯ near threshold

The process e+e−→NN¯ is studied nearby a threshold with account for polarizations of all initial and final particles. The nucleon polarization ζN reveals a strong energy dependence due to that of the nucleon electromagnetic form factors GE(Q2) and GM(Q2) caused by the final-state interaction of nucleons. It is shown that the modulus of the ratio of these form factors and their relative phase can be determined by measuring ζN along with the differential cross section. The polarization degree is analyzed using Paris NN¯ optical potential for calculation of the form factors. It turns out that |ζN| is high enough in a rather wide energy range above the threshold. Being especially high for longitudinally polarized beams, |ζN| is noticeable even if both e+e− beams are unpolarized.