Initial state radiation in $e^{+}{e}^{-}$ annihilation

In two earlier papers it was demonstrated that Lorentzian and Galilean symmetries could both be useful in the analysis of the annihilation reaction $e^{+}{e}^{-}\to \gamma \mathrm{\Lambda }(\to p{\pi }^{-})\bar{\mathrm{\Lambda }}(\to \bar{p}{\pi }^{+})$. It was also demonstrated that any pair of hyperon form factors would be acceptable, but that the $\{G_E,G_M\}$ pair would probably be the simplest one to handle.