We discuss various experiments on e + e − annihilation into hadrons relevant to the problem of the muon anomalous magnetic moment. They include a status of the ISR measurements of the e + e − → π + π − as well as studies of numerous hadronic final states in experiments with the CMD-3 and SND detectors at the VEPP-2000 e + e − collider.

We report results of experiments performed with the KEDR detector at the VEPP-4M e + e − collider. They include precise measurement of the D 0 and D ± meson masses, determination of the ψ(3770)resonance parameters, and a search for narrow resonances in e + e − annihilation at center-of-mass energies between 1.85 and 3.1 GeV.

This paper reports a current status of the measurements of the hadronic cross sections in the c.m. energy range from 0.32 to 2.0 GeV with the CMD-3 detector at the VEPP-2000 electron-positron collider. The overall size of the data, acquired by the CMD-3 in the runs of 2010-2013 and 2017-2018 years, is about 160 pb −1 . The results of data analysis for various exclusive modes of e + e − →hadrons are described.

The current status of the Standard Model predictions for the muon anomalous magnetic moment is described. Various contributions expected in the Standard Model are discussed. After the reevaluation of the leading-order hadronic term based on the new e + e − data, the theoretical prediction is more than three standard deviations lower than the experimental value.

We report results of experiments performed with the KEDR detector at the VEPP-4M e + e − collider. They include precise measurement of the D 0 and D ± meson masses, determination of the ψ(3770)resonance parameters, and a search for narrow resonances in e + e − annihilation at center-of-mass energies between 1.85 and 3.1 GeV.