Helicity amplitudes for the small angle lepton pair production in e^+e^- or μ^+ μ^- collisions

E. A. Kuraev, A. Schiller, V. G. Serbo +1

The lepton pair production $e^{-}{e}^{+}\to e^{-}{e}^{+}{l}^{-}{l}^{+}$ or ${\mu }^{-}{\mu }^{+}\to {\mu }^{-}{\mu }^{+}{l}^{-}{l}^{+}$ is studied in the dominant cross section region of scattering angles ${m_j}/{E_j} \stack…