KLOE Results on Hadronic Cross Section

The KLOE experiment at the Frascati φ-factory DAΦNE has measured the hadronic cross section σ(e+e- → π+π-γISR) using two different selection criteria for the Initial State Radiation (ISR) photon: (i) requiring the photon emission at small polar angle and (ii) detecting the photon at large polar angle in the electromagnetic calorimeter. Using a theoretical radiator function we extract the non-radiative cross section σ(e+e- → π+π-) and we compute the π+π- contribution to the anomalous magnetic moment of the muon. Results presented in this paper come from the analysis of data collected in 2002 (240 pb-1 of integrated luminosity) with an improved systematic uncertainty compared to a published KLOE analysis, which was based on 2001 data. (author)