Speaker
Roland Waldi
(University of Rostock)
Description
The BABAR Collaboration has an intensive program studying hadronic cross sections in
low-energy e+e- annihilations, which are accessible with data taken near the Upsilon(4S) 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 sigma
difference between the predicted and the experimental values.
We have previously published results on a number of processes with two to six hadrons in the final state.
Currently, the largest uncertainty on the calculation of the hadronic contribution in the energy region between 1 and 2 GeV stems from the e+e- -> pi+ pi- pi0 pi0 cross section.
A new precise measurement of this process is presented here, together with measurement
of other low-multiplicity channels, such as e+e- -> pi+ pi- eta.
