e+e− hadronic cross section and the muon g − 2

Abstract

After a brief introduction to the muon anomalous magnetic moment, the current status of the (g − 2)µ measurement is given. The three standard deviations of discrepancy between aµ calculations and the direct measurement by the E821 experiment at the Brookhaven National Laboratory (USA) calls for more precise measurements of the e+e− hadronic cross section. This article contains a not inclusive review of the main results and the state of the art on the hadronic cross section measurements from BABAR and other experiments.