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

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  • Authors:
  • CDF Collaboration


Drell-Yan lepton pairs are produced in the process pp→μ+μ+X through an intermediate γ/Z boson. The forward-backward asymmetry in the polar-angle distribution of the μas a function of the invariant mass of the μ+μ pair is used to obtain the effective leptonic determination sin2θlepteff 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 9.2 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 sin2θlepteff 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−M2W/M2Z, the measurement yields
sin2θW=0.2233±0.0009, or equivalently a W-boson mass of 80.365±0.047 GeV/c2. The value of the W-boson mass is in agreement with previous determinations in electron-positron collisions and at the Tevatron collider.

Bibliographical metadata

Original languageEnglish
Number of pages21
JournalPhysical Review D (Particles, Fields, Gravitation and Cosmology)
Issue number7
Publication statusPublished - 4 Apr 2014