Hadronic vacuum polarization in $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}$ process bellow 3 GeV

Abstract

The interference effect between leptonic radiative corrections and hadronic polarization functions is calculated via optical theorem for $\mu -$pair productions. It is achieved within the use of the last data for ${\sigma }_h(e^{+}{e}^{-}\to hadrons)$ from SND,CMD,CMD-2,BABAR and BESSIII experimental Collaborations. The paper takes into account specific experimental conditions and the result is compared with KLOE experiment for ${\mu }^{-}{\mu }^{+}$ production at $\varphi$ meson energy. Small, but non-negligible tension between theory and experiment is discussed.

Comments: 7p, 3f, essential info inside