Speaker
Description
After more than 60 years since the first measurements, the study of $e^+e^-$ annihilation processes at low energies are still
a great source of information in an energy region where perturbative Quantum Chromodinamyc cannot be used.
The hadronic cross section is also the experimental input for the theoretical
calculation of the hadronic contribution to the anomalous magnetic moment of the muon,
allowing for precise tests of the Standard Model and searches for New Physics effects.
A great improvement on the precision of hadronic cross section measurements has been obtained in the last two decades, thanks to new generation experiments at high-luminosity $e^+e^-$ colliders and novel analysis methods.
We present here the main results obtained for a variety of multi-hadronic final states, including the most recent measurements of the process $e^+e^-\to \pi^+\pi^-$, and discuss the impact of the cross section measurements on the muon $g-2$ calculation.
We then present the current status of the comparison between theory and experiment in light of the new
direct measurement at the $g-2$ experiment at FermiLab and of recent lattice calculations.
