Two-photon exchange effects in $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ at small $\sqrt{s}$

Zhong-Hua Zhao, Hui-Yun Cao, Hai-Qing Zhou

In this work, the two-photon-exchange (TPE) effects in $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ at small $\sqrt{s}$ are discussed within a hadronic model. In the limit $m_e\to 0$, the…