Measurement of e+e− → π+π−π0 at BABAR and calculation of (g−2)μ
Résumé
We present a study of the process at BABAR using the initial-state radiation technique. The analysis is based on the full BABAR data set, , recorded at and near the resonance. From the fit to the measured three pion mass spectrum we determine the products () for the ω and ϕ resonances, and the branching ratio (). The latter isospin-breaking decay is observed with 6σ significance. The cross section is measured from 0.62 GeV to 3.5 GeV. The measured cross section is used to calculate the leading-order hadronic contribution to the muon anomalous magnetic moment from this exclusive final state with improved accuracy. A short status is given on the current discrepancy between the predicted value and the measured value of the muon anomalous magnetic moment.