Two recent precision measurements of the Standard Model parameters using 1.7 fb−1 of e+e− data collected with the KLOE detector at DAΦNE are presented:
Dalitz plot distribution for the η→π+π−π0 decay is studied with the world's largest sample of ∼4.7⋅106 events from e+e−→ϕ→ηγ. The statistical uncertainty of all parameters is improved by a factor of two with respect to the earlier measurements. The data are used as input in dispersive calculations to determine ratio of the light quark masses.
Running of the effective QED coupling constant α(s) in the time-like region 0.600<√s<0.980 GeV is studied using the Initial-State Radiation process e+e−→μ+μ−γ. More than 5σ significance of the hadronic contribution to the running of α(s) is seen, which is the strongest direct evidence achieved in a single measurement. By using the e+e−→π+π− cross section measured by KLOE, the real and imaginary parts of α(s) have been extracted. From a fit of the real part the branching ratio BR(ω→μ+μ−)=(6.6±1.4stat±1.7syst)⋅10−5 has been determined.
