Two-photon exchange effects in $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ and time-like pion electromagnetic form factor

Hong-Yu Chen, Hai-Qing Zhou

The two-photon-exchange (TPE) effects in the process $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ at large momentum transfer are discussed within the perturbative QCD (pQCD). The contributions from…