Measurements of inclusive W and Z cross sections in p(p)over-bar collisions at root s=1.96 TeV RID G-1087-2011 RID E-4473-2011

We report the first measurements of inclusive W and Z boson cross-sections times the corresponding leptonic branching ratios for pp collisions at root 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(W) x Br(p (p) over bar -> W -> l nu) = 2.749 +/- 0.010(stat.) +/- 0.053(syst.) +/- 0.165(lum.) nb and sigma(gamma*/Z) x Br(p (p) over bar ->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/c2. We compute the ratio R of the W -> l nu 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 -> l nu) = 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.