Hadron production in e⁺e⁻collisions at BABAR and implications on the muon anomalous magnetic moment

Institute of Nuclear Physics J.G.-University Mainz, 55128 Mainz, GERMANY

^a e-mail: hafner@kph.uni-mainz.de

Published online: 6 May 2014

Abstract

The BABAR Collaboration has an intensive program of studying hadronic cross sections at low-energy e⁺e⁻ collisions, accessible via initial-state radiation. Our measurements allow significant improvements in the precision of the predicted value of the muon anomalous magnetic moment. These improvements are necessary for shedding light on the current ∼ 3.5σ difference between the predicted and the experimental values. We have published results on a number of processes with two to six hadrons in the final state. We report here the results of recent studies with the final states which constitute the main contribution to the hadronic cross section in the energy region between 1 and 3 GeV, as e⁺e⁻ → K⁺K⁻, e⁺e⁻ → K_S⁰K_L⁰ and e⁺e⁻ → 4 hadrons.