Measurement of the Effective Weak Mixing Angle in p p ¯ →Z/γ∗ →e+e- Events

Abstract

We present a measurement of the fundamental parameter of the standard model, the weak mixing angle sin2θeffℓ which determines the relative strength of weak and electromagnetic interactions, in pp¯→Z/γ∗→e+e- events at a center of mass energy of 1.96 TeV, using data corresponding to 9.7 fb-1 of integrated luminosity collected by the D0 detector at the Fermilab Tevatron. The effective weak mixing angle is extracted from the forward-backward charge asymmetry as a function of the invariant mass around the Z boson pole. The measured value of sin2θeffℓ=0.23147±0.00047 is the most precise measurement from light quark interactions to date, with a precision close to the best LEP and SLD results.