4 research outputs found
Precision measurements of the top quark mass from the Tevatron in the pre-LHC era
The top quark is the heaviest of the six quarks of the Standard Model.
Precise knowledge of its mass is important for imposing constraints on a number
of physics processes, including interactions of the as yet unobserved Higgs
boson. The Higgs boson is the only missing particle of the Standard Model,
central to the electroweak symmetry breaking mechanism and generation of
particle masses. In this Review, experimental measurements of the top quark
mass accomplished at the Tevatron, a proton-antiproton collider located at the
Fermi National Accelerator Laboratory, are described. Topologies of top quark
events and methods used to separate signal events from background sources are
discussed. Data analysis techniques used to extract information about the top
mass value are reviewed. The combination of several most precise measurements
performed with the two Tevatron particle detectors, CDF and \D0, yields a value
of \Mt = 173.2 \pm 0.9 GeV/.Comment: This version contains the most up-to-date top quark mass averag
Measurements of Inclusive W and Z Cross Sections in p-pbar Collisions at sqrt{s} =1.96 TeV
We report the first measurements of inclusive W and Z boson cross sections
times the corresponding leptonic branching ratios for p pbar collisions at
sqrt{s} = 1.96 TeV based on the decays of the W and Z bosons into electrons and
muons. The data were recorded with the CDF II detector at the Fermilab Tevatron
and correspond to an integrated luminosity of 72.0 +/- 4.3 pb-1. We test e-mu
lepton universality in W decays by measuring the ratio of the W->mu nu to W->e
nu cross sections and determine a value of 0.991 +/- 0.004(stat.) +/-
0.011(syst.) for the ratio of W-l-nu couplings (g_mu/g_e). Since there is no
sign of non-universality, we combine our cross section measurements in the
different lepton decay modes and obtain sigma*BR(W->lnu) = 2.749 +/-
0.010(stat.) +/- 0.053(syst.) +/- 0.165(lum.) nb and
sigma*BR(gamma*/Z->ll)=254.9 +/- 3.3(stat.) +/- 4.6(syst.) +/- 15.2(lum.) pb
for dilepton pairs in the mass range between 66 GeV/c^2 and 116 GeV/c^2. We
compute the ratio R of the W->lnu to Z->ll cross sections taking all
correlations among channels into account and obtain R=10.84 +/- 0.15(stat.) +/-
0.14(syst.) including a correction for the virtual photon exchange component in
our measured gamma*/Z->ll cross section. Based on the measured value of R, we
extract values for the W leptonic branching ratio, BR(W->lnu) =0.1082 +/-
0.0022; the total width of the W boson, Gamma(W) =2092 +/- 42 MeV; and the
ratio of W and Z boson total widths, Gamma(W)/Gamma(Z) = 0.838 +/- 0.017. In
addition, we use our extracted value of Gamma(W) whose value depends on various
electroweak parameters and certain CKM matrix elements to constrain the V_CS
CKM matrix element, |V_CS| = 0.976 +/- 0.030.Comment: 88 pages, 37 figures, published J. Phys.