Measurement of σ(e+e−→π+π−γ)σ(e+e−→π+π−γ) and extraction of σ(e+e−→π+π−)σ(e+e−→π+π−) below 1 GeV with the KLOE detector

We have measured the cross section σ(e+e−→π+π−γ)σ(e+e−→π+π−γ) at an energy W=mϕ=1.02 GeVW=mϕ=1.02 GeV with the KLOE detector at the electron–positron collider DAΦNEDAΦNE. From the dependence of the cross section on the invariant mass of the two-pion system, we extract σ(e+e−→π+π−)σ(e+e−→π+π−) for the mass range 0.35pion form factor and the hadronic contribution to the muon anomaly, aμaμ.