Speaker
Описание
An up-to-date compilation of the world data on the $e^+e^- \to hadrons$ total cross section is used for dispersive evaluation of the leading order hadronic contribution to the muon anomalous magnetic moment $a_\mu = (g_\mu-2)/2$. Our value $a_\mu(had,LO) = (696.2 \pm 1.9_{e^+e^- exp.} \pm 2.1_{syst.})\times 10^{-10}$ is consistent with recent estimates by other groups. An impact of a recent $\sigma(e^+e- \to \pi^+\pi^-)$ measurement by the CMD-3 experiment is discussed.
The SM prediction of $a_\mu$ including our $a_\mu(had,LO)$ estimate $a_\mu^{\mathrm{SM}} = 11~659~184(4) \times 10^{-10}$ is in $\sim 4.7\sigma$ tension with the experimental value $a_\mu^{exp} = 11~659~205.9 (2.2) \times 10^{-10}$ [FNAL g-2 Collaboration, Phys. Rev. Lett. 131, 161802 (2023)].
