Measurement of sin²θ^lept_eff using e⁺e⁻ pairs from γ^∗/Z bosons produced in pp collisions at a center-of-momentum energy of 1.96 TeV

At the Fermilab Tevatron proton-antiproton (pp) collider, Drell-Yan lepton pairs are produced in the process pp→e⁺e⁻+X through an intermediate γ^∗/Z boson. The forward-backward asymmetry in the polar-angle distribution of the e⁻ as a function of the e⁺e⁻ -pair mass is used to obtain sin²θ^lept_eff, the effective leptonic determination of the electroweak-mixing parameter sin²θ_W. The measurement sample, recorded by the Collider Detector at Fermilab (CDF), corresponds to 9.4 fb⁻¹ of integrated luminosity from pp collisions at a center-of-momentum energy of 1.96 TeV, and is the full CDF Run II data set. The value of sin²θ^lept_eff is found to be 0.23248 ± 0.00053. The combination with the previous CDF measurement based on μ⁺μ⁻ pairs yields sin²θ^lepteff = 0.23221 ± 0.00046. This result, when interpreted within the specified context of the standard model assuming sin²θ_W=1−M²_W/M_2Z and that the W- and Z-boson masses are on-shell, yields sin²θ^W=0.22400±0.00045, or equivalently a W-boson mass of 80.328 ± 0.024 GeV/c2.