We report the first measurements of inclusive W and Z boson cross sections times the corresponding leptonic branching ratios for pp collisions at √ 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
4Tevatron and correspond to an integrated luminosity of 72.0 ± 4.3 pb −1 . We test e-µ lepton universality in W decays by measuring the ratio of the W → µν to W → eν cross sections and determine a value of 0.991 ± 0.004(stat.) ± 0.011(syst.) for the ratio of W −ℓ−ν couplings (gµ/ge). Since there is no sign of non-universality, we combine our cross section measurements in the different lepton decay modes and obtain σW ×Br(pp → W → ℓν) = 2.749 ± 0.010(stat.) ± 0.053(syst.) ± 0.165(lum.) nb and σ γ * /Z × Br(pp → γ * /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 → ℓν 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 γ * /Z → ℓℓ cross section. Based on the measured value of R, we extract values for the W leptonic branching ratio, Br(W → ℓν) = 0.1082 ± 0.0022; the total width of the W boson, Γ(W ) = 2092 ± 42 MeV; and the ratio of W and Z boson total widths, Γ(W )/Γ(Z) = 0.838 ± 0.017. In addition, we use our extracted value of Γ(W ) whose value depends on various electroweak parameters and certain CKM matrix elements to constrain the Vcs CKM matrix element, |Vcs| = 0.976± 0.030.
Submarine landslides, which commonly develop along subduction margins at the front of accretionary prisms, have recently been recognized as one of the most serious geohazards. To investigate the mechanical processes involved in the development of these landslides, a series of sandbox experiments were performed, and the results analyzed using the Digital Image Correlation (DIC) technique. Numerous slope failures, which may be analogous to natural submarine landslides, were produced on the model surface. The slope failures can be classified as follows: Type I failures, which are relatively small but are frequently developed on the lower parts of the slope; and Type II failures, which are relatively large and cover the entire slope, but occur less frequently. Detailed observations reveal that the failure process can be divided into four stages: 1) pre-failure, 2) steepening of the lower slope, 3) Type I failure, and 4) Type II failure. The minor Type I slides act as precursors of major Type II failures. Each slope failure produces a topographic undulation, triggering events in adjacent areas and a lateral migration of discrete slope failures. Although such experiments provide useful insight into slope failure processes, a detailed 3D analysis of the failed sediment is vital if we are to understand the precise history of thrust activity at subduction margins. Recent and Miocene accretionary prisms along the Nankai Trough, Japan, display the geometric and lithologic characteristics of Type I and Type II failures in their slide deposits.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.