New precise measurement of the $e^+e^- \rightarrow \pi^+\pi^-(\gamma)$ cross section with BABAR

Abstract

The BABAR experiment participates to the global endeavor for a precise prediction of the anomalous magnetic moment of the muon by evaluating the contribution from hadronic vacuum polarization, in particular through cross section measurements of hadronic final states from $e^+e^-$ collisions. After a first measurement in 2009 of the largest input that comes from the $e^+e^- \rightarrow \pi^+\pi^-(\gamma)$ cross section, we present preliminary results from a new study on 460 ${\rm fb}^{-1}$ of BABAR data, involving a blind and independent procedure. The results of the two analyses are shown to be consistent.