Determination of G{cyrillic}ee of the Υ(1 S) and Υ(2 S) resonances, and measurement of R at W=9.39 GeV

Using the Crystal Ball detector operating at the DORIS II storage ring we have measured the leptonic partial widthsГ ee of the Υ(1S) and Υ(2S) resonances. We find $$\Gamma _{ee} (\Upsilon (1S)) = 1.34 \pm 0.03 \pm 0.06keV$$ and $$\Gamma _{ee} (\Upsilon (2S)) = 0.56 \pm 0.04 \pm 0.02keV.$$ The effect onГ ee of applying different prescriptions for radiative corrections is discussed. We also measureR, the ratio of non-resonant hadronic cross section to the Born cross section of μ pair production, at c.m. energyW=9.39 GeV to beR=3.48±0.04±0.16.