Indirect measurement of ${\sin }^2\hat{I}{¸}_W$ (or $M_W$) using $\hat{I}{¼}^{+}\hat{I}{¼}^{-}$ pairs from $γ^*/Z$ bosons produced in $p\bar{p}$ collisions at a center-of-momentum energy of 1.96 TeV

Abstract

Drell-Yan lepton pairs are produced in the process $p\bar{p}\to \hat{I}{¼}^{+}\hat{I}{¼}^{-}+X$ through an intermediate $γ^*/Z$ boson. The forward-backward asymmetry in the polar-angle distribution of the $\hat{I}{¼}^{-}$ as a function of the invariant mass of the $\hat{I}{¼}^{+}\hat{I}{¼}^{-}$ pair is used to obtain the effective leptonic determination ${\sin }^2\hat{I}{¸}_{eff}^{lept}$ of the electroweak-mixing parameter ${\sin }^2\hat{I}{¸}_W$, from which the value of ${\sin }^2\hat{I}{¸}_W$ is derived assuming the standard model. The measurement sample, recorded by the Collider Detector at Fermilab (CDF), corresponds to 9.2 fb-1 of integrated luminosity from $p\bar{p}$ collisions at a center-of-momentum energy of 1.96 TeV, and is the full CDF Run II data set. The value of ${\sin }^2\hat{I}{¸}_{eff}^{lept}$ is found to be 0.2315 +- 0.0010, where statistical and systematic uncertainties are combined in quadrature. When interpreted within the context of the standard model using the on-shell renormalization scheme, where ${\sin }^2\hat{I}{¸}_W=1-M_W^2/M_Z^2$, the measurement yields ${\sin }^2\hat{I}{¸}_W$ = 0.2233 +- 0.0009, or equivalently a W-boson mass of 80.365 +- 0.047 GeV/c^2. The value of the W-boson mass is in agreement with previous determinations in electron-positron collisions and at the Tevatron collider.