A precise measurement of sin² θ _W at low Q² in Møller scattering

Abstract

The E-158 experiment has performed the first measurement of the parity-violating asymmetry in electron-electron (Møller) scattering using a 50 GeV polarized electron beam and a fixed unpolarized liquid hydrogen target in End Station A at SLAC. Our preliminary results is: A _PV =–128± 14(stat)± 12(syst) × 10^–9. From this quantity we extract $\sin^2 \theta_W(Q^2=0.026 GeV/c^2)_{\overline{MS}}=0.2403\pm 0.0010(stat)\pm 0.0009(syst)$, consistent with the Standard Model prediction.

PACS: 11.30.Er Charge conjugation, parity, time reversal, and other discrete symmetries – 12.15.Lk Electroweak radiative corrections – 12.15.Mm Neutral currents – 13.66.Lm Processes in other lepton-lepton interactions – 13.88.+e Polarization in interactions and scattering – 14.60.Cd Electrons