Hadronic vacuum polarization and e⁺e⁻ → μ⁺μ⁻ cross section: Reanalysis with new precise data for σ_h with 4π final states included

Abstract

Abstract. The interference effect between leptonic radiative corrections and hadronic polarization functions is calculated via optical theorem for µ−pair production in vicinity of narrow resonances. Within seven most dominant exclusive channels of the production cross section σ h (e + e − → hadrons) one achieves high acuracy which is necessary for the comparison with experiments. The result is compared with KLOE and KLOE2 experiments for µ − µ + and µ − µ + γ productions at φ and ω/ρ meson energy.

Timelike behavior of the electromagnetic form factor in the functional formalism

“…In this figure we compare the norm square and compare with world averaged experimental data for F . The averaged experimental based on data of BABAR, BESS, CMD/SND and KLOE experiments [1] were fitted as described in [82], noting there is negligibly small experimental error 0.5% on the ρ meson peak. Within used approximation the derivation of desired dispersion relation (4.8) is quite straightforward, albeit a bit lengthy and it is delegated into the Appendix C of this work.…”