Pion form factor measurements at KLOE via radiative return method

The KLOE experiment at the φ factory DAΦNE is using ISR to measure σ(e+e-→π+π-γ) with an absolute normalisation obtained from Bhabha scattering. ππγ events are obtained with two different selection criteria: (a) requiring photon emission at small angles (SA) (b) tagged photons detected in the calorimeter (LA). With the two samples we cover the complete range of 2mπ <√(s) = Mππ < mφ. Using a theoretical radiator function H(s) we extract the pion form factor Fπ2 and obtain the two-pion contribution to aμhad. Results to be presented come from the analysis of 240 pb-1 collected in 2002, with very small statistical error (∝0.1%) and improved systematic uncertainties (∝1%). Furthermore, using a run of 200 pb-1 of data taken at √(s)=1 GeV, we can minimize the contribution of resonant background processes.