Observation Of Parity Nonconservation In Moller Scattering

We report a measurement of the parity-violating asymmetry in fixed target electron-electron (Moller) scattering: A(PV)=[-175+/-30(stat)+/-20(syst)]x10(-9). This first direct observation of parity nonconservation in Moller scattering leads to a measurement of the electron's weak charge at low energy Q(W)(e)=-0.053+/-0.011. This is consistent with the standard model expectation at the current level of precision: sin(2)theta(W)(M-Z)((MS) over bar) = 0.2293+/-0.0024(stat)+/-0.0016(syst)+/-0.0006(theory).