Effects of electroweak radiative corrections in polarized low-energy electron-positron annihilation into lepton pairs

Complete one-loop electroweak radiative corrections to the cross section of the process $e^+e^- \to \mu^-\mu^+ (\tau^-\tau^+)$ are evaluated with the help of the SANC system. Higher-order contributions of the initial state radiation are computed in the QED structure function formalism. Numerical results are given for the center-of-mass energy range $\sqrt s = 5$, $7$ GeV for various polarization degrees of the initial particles. This study is a contribution to the research program of the Super Charm-Tau Factory project being under development in Sarov, Russia.