Precision measurement of the weak mixing angle in Moller scattering

We report on a precision measurement of the parity-violating asymmetry in fixed target electron-electron (Moller) scattering: A(PV)=[-131 +/- 14(stat)+/- 10(syst)]x10(-9), leading to the determination of the weak mixing angle sin(2)theta(W)(eff)=0.2397 +/- 0.0010(stat)+/- 0.0008(syst), evaluated at Q(2)=0.026 GeV2. Combining this result with the measurements of sin(2)theta(W)(eff) at the Z(0) pole, the running of the weak mixing angle is observed with over 6 sigma significance. The measurement sets constraints on new physics effects at the TeV scale.