Indirect measurement of sin2θW (or MW) using μ+μ- pairs from γ* /Z bosons produced in p p ̄ collisions at a center-of-momentum energy of 1.96 TeV INDIRECT MEASUREMENT of sin2θW (OR ... T. AALTONEN et al.

摘要

Drell-Yan lepton pairs are produced in the process pp̄→μ+μ- +X through an intermediate γ*/Zboson. The forward-backward asymmetry in the polar-angle distribution of the μ- as a function of the invariant mass of the μ+μ- pair is used to obtain the effective leptonic determination sin2θefflept of the electroweak-mixing parameter sin2θW, from which the value of sin2θW is derived assuming the standard model. The measurement sample, recorded by the Collider Detector at Fermilab (CDF), corresponds to 9.2fb-1 of integrated luminosity from pp̄ collisions at a center-of-momentum energy of 1.96 TeV, and is the full CDF Run II data set. The value of sin2θefflept 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 sin2θW=1-MW2/MZ2, the measurement yields sin2θW=0.2233±0.0009, or equivalently a W-boson mass of 80.365±0.047GeV/c2. The value of the W-boson mass is in agreement with previous determinations in electron-positron collisions and at the Tevatron collider. © 2014 American Physical Society.