An analysis of high-transverse-momentum electrons using data from the Collider Detector at Fermilab (CDF) of p¯p collisions at s=1800 GeV yields values of the production cross section times branching ratio for W and Z0 bosons of σ(p¯p→WX→eνX)=2.19±0.04(stat)±0.21(syst) nb and σ(p¯p→Z0X→e+e−X)=0.209±0.013(stat)±0.017(syst) nb. Detailed descriptions of the CDF electron identification, background, efficiency, and acceptance are included. Theoretical predictions of the cross sections that include a mass for the top quark larger than the W mass, current values of the W and Z0 masses, and higher-order QCD corrections are in good agreement with these measured values.

First measurements of the W -> lnu and Z/gamma* -> ll (l = e, mu) production cross sections in proton-proton collisions at sqrt(s) = 7 TeV are presented using data recorded by the ATLAS experiment at the LHC. The results are based on 2250 W -> lnu and 179 Z/gamma* -> ll candidate events selected from a data set corresponding to an integrated luminosity of approximately 320 nb-1. The measured total W and Z/gamma*-boson production cross sections times the respective leptonic branching ratios for the combined electron and muon channels are $\stotW$ * BR(W -> lnu) = 9.96 +- 0.23(stat) +- 0.50(syst) +- 1.10(lumi) nb and $\stotZg$ * BR(Z/gamma* -> ll) = 0.82 +- 0.06(stat) +- 0.05(syst) +- 0.09(lumi) nb (within the invariant mass window 66 < m_ll < 116 GeV). The W/Z cross-section ratio is measured to be 11.7 +- 0.9(stat) +- 0.4(syst). In addition, measurements of the W+ and W- production cross sections and of the lepton charge asymmetry are reported. Theoretical predictions based on NNLO QCD calculations are found to agree with the measurements.

We present a measurement of the ratio σB(W→eν)σB(Z0→e+e−) in p¯p collisions at s=1.8 TeV The data represent an integrated luminosity of 21.7 pb−1 from the 1992-1993 run of the Collider Detector at Fermilab. We find σB(W→eν)σB(Z0→e+e−)=10.90±0.32(stat)±0.29(syst). From this value, we extract a value for the W width, Γ(W)=2.064±0.061(stat)±0.059(syst) GeV, and the branching ratio, Γ(W→eν)Γ(W)=0.1094±0.0033(stat)±0.0031(syst), and we set a decay-mode-independent limit on the top quark mass mtop>62 GeV/c2 at the 95% C.L.

We present the results of a search in p¯p collisions at s=1.8 TeV for the top quark decaying to a charged Higgs boson (H±). We search for dilepton final states from the decay chain tt¯→HH (or HW, or WW) + bb¯→ll+X. In a sample of 19.3 pb−1 collected during 1992-93 with the Collider Detector at Fermilab, we observe 2 events with a background estimation of 3.0 ± 1.0 events. Limits at 95% C.L. in the (Mtop,MH±) plane are presented. For the case Mtop<MW+Mb, we exclude at 95% C.L. the entire (Mtop,MH±) plane for the branching ratio B(H→τν) larger than 75%. We also interpret the results in terms of the parameter tan β of two-Higgs-doublet models.

The charge asymmetry has been measured using $19,039W$ decays recorded by the CDF detector during the 1992-93 run of the Tevatron Collider. The asymmetry is sensitive to the ratio of $d$ and $u$ quark distributions to $x<0.01$ at $Q~2 \approx M_W~2$, where nonperturbative effects are minimal. It is found that of the two current sets of parton distributions, those of Martin, Roberts and Stirling (MRS) are favored over the sets most recently produced by the CTEQ collaboration. The $W$ asymmetry data provide a stronger constraints on $d/u$ ratio than the recent measurements of $F_2~{\mu n}/F_2~{\mu p}$ which are limited by uncertainties originating from deutron corrections.

The W+jet angular distribution is measured using W→eν events recorded with the Collider Detector at Fermilab (CDF) during the 1988-89 and 1992-93 Tevatron runs. The data agree well with both a leading order and a next-to-leading order theoretical prediction. The shape of the angular distribution is similar to that observed in photon + jet data and significantly different from that observed in dijet data.

We present a measurement of $\sigma \cdot B(W \rightarrow e \nu)$ and $\sigma \cdot B(Z~0 \rightarrow e~+e~-)$ in proton - antiproton collisions at $\sqrt{s} =1.8$ TeV using a significantly improved understanding of the integrated luminosity. The data represent an integrated luminosity of 19.7 pb$~{-1}$ from the 1992-1993 run with the Collider Detector at Fermilab (CDF). We find $\sigma \cdot B(W \rightarrow e \nu) = 2.49 \pm 0.12$nb and $\sigma \cdot B(Z~0 \rightarrow e~+e~-) = 0.231 \pm 0.012$nb.

We report two complementary measurements of the WW+WZ cross section in the final state consisting of an electron or muon, missing transverse energy, and jets, performed using p\bar{p} collision data at sqrt{s} = 1.96 TeV collected by the CDF II detector. The first method uses the dijet invariant mass distribution while the second more sensitive method uses matrix-element calculations. The result from the second method has a signal significance of 5.4 sigma and is the first observation of WW+WZ production using this signature. Combining the results gives sigma_{WW+WZ} = 16.0 +/- 3.3 pb, in agreement with the standard model prediction.

This Letter describes the current most precise measurement of the $W$ boson pair production cross section and most sensitive test of anomalous $WW\gamma$ and $WWZ$ couplings in $p \bar p$ collisions at a center-of-mass energy of 1.96 TeV. The $WW$ candidates are reconstructed from decays containing two charged leptons and two neutrinos, where the charged leptons are either electrons or muons. Using data collected by the CDF II detector from 3.6 fb$^{-1}$ of integrated luminosity, a total of 654 candidate events are observed with an expected background contribution of $320 \pm 47$ events. The measured total cross section is $\sigma (p \bar p \to W^+ W^- + X) = 12.1 \pm 0.9 \textrm{(stat)} ^{+1.6}_{-1.4} \textrm{(syst)}$ pb, which is in good agreement with the standard model prediction. The same data sample is used to place constraints on anomalous $WW\gamma$ and $WWZ$ couplings.

We present the first measurement of the production cross section of a W boson with a single charm quark (c) in p-pbar collisions at sqrt(s)=1.96 TeV, using soft muon tagging of c jets. In a data sample of ~1.8 fb-1, recorded with the CDF II detector at the Fermilab Tevatron, we select events with W+1 or 2 jets. We use the charge correlation between the W and the muon from the semileptonic decay of a charm hadron to extract the Wc signal. We measure sigma_{Wc}(p_{Tc}>20 GeV/c, |\eta_c|<1.5)\times BR(W->\ell\nu) = 9.8+/-3.2 pb, in agreement with theoretical expectations.

The WWgamma triple gauge boson coupling parameters are studied using p-pbar -> l nu gamma + X (l = e,mu) events at sqrt(s) = 1.96 TeV. The data were collected with the DO detector from an integrated luminosity of 162 pb^{-1} delivered by the Fermilab Tevatron Collider. The cross section times branching fraction for p-pbar -> W(gamma) + X -> l nu gamma + X with E_T^{gamma} > 8 GeV and Delta R_{l gamma} > 0.7 is 14.8 +/- 1.6 (stat) +/- 1.0 (syst) +/- 1.0 (lum) pb. The one-dimensional 95% confidence level limits on anomalous couplings are -0.88 < Delta kappa_{gamma} < 0.96 and -0.20 < lambda_{gamma} < 0.20.

We report the first observation of the associated production of a W boson and a Z boson. This result is based on 1.1 fb-1 of integrated luminosity from ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We observe 16 WZ candidates passing our event selection with an expected background of 2.7 +/- 0.4 events. A fit to the missing transverse energy distribution indicates an excess of events compared to the background expectation corresponding to a significance equivalent to six standard deviations. The measured cross section is sigma(ppbar -> WZ) = 5.0^{+1.8}_{-1.6} pb, consistent with the standard model expectation.

We present a measurement of the fraction of inclusive $W$+jets events produced with net charm quantum number $\pm1$, denoted $W$+$c$-jet, in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV using approximately 1~fb$^{-1}$ of data collected by the D0 detector at the Fermilab Tevatron Collider. We identify the $W$+jets events via the leptonic $W$ boson decays. Candidate $W$+$c$-jet events are selected by requiring a jet containing a muon in association with a reconstructed $W$ boson and exploiting the charge correlation between this muon and $W$ boson decay lepton to perform a nearly model-independent background subtraction. We measure the fraction of $W$+$c$-jet events in the inclusive $W$+jets sample for jet $p_{T}>20$ GeV and pseudorapidity $|\eta|<2.5$ to be 0.074$\pm0.019$(stat.)$\pm^{0.012}_{0.014}$(syst.), in agreement with theoretical predictions. The probability that background fluctuations could produce the observed fraction of $W$+$c$-jet events is estimated to be $2.5\times 10^{-4}$, which corresponds to a 3.5 $\sigma$ statistical significance.

We present the first model-independent measurement of the helicity of $W$ bosons produced in top quark decays, based on a 1 fb$^{-1}$ sample of candidate $t\bar{t}$ events in the dilepton and lepton plus jets channels collected by the D0 detector at the Fermilab Tevatron $p\bar{p}$ Collider. We reconstruct the angle $\theta^*$ between the momenta of the down-type fermion and the top quark in the $W$ boson rest frame for each top quark decay. A fit of the resulting \costheta distribution finds that the fraction of longitudinal $W$ bosons $f_0 = 0.425 \pm 0.166 \hbox{(stat.)} \pm 0.102 \hbox{(syst.)}$ and the fraction of right-handed $W$ bosons $f_+ = 0.119 \pm 0.090 \hbox{(stat.)} \pm 0.053 \hbox{(syst.)}$, which is consistent at the 30% C.L. with the standard model.

We present measurements of the process $p\bar{p} \to WZ+X \to \ell^{\prime} \nu_{\ell^{\prime}} \ell \bar{\ell}$ at $\sqrt{s}=1.96$ TeV, where $\ell$ and $\ell^{\prime}$ are electrons or muons. Using 1 fb$^{-1}$ of data from the D0 experiment, we observe 13 candidates with an expected background of $4.5\pm0.6$ events and measure a cross section $\sigma(WZ)=2.7^{+1.7}_{-1.3}$ pb. From the number of observed events and the $Z$ boson transverse momentum distribution, we limit the trilinear $WWZ$ gauge couplings to $-0.17 \le \lambda_Z \le 0.21$ $(\Delta \kappa_Z = 0)$ at the 95% C.L. for a form factor scale $\Lambda=2$ TeV. Further, assuming that $\Delta g^Z_1 = \Delta\kappa_Z$, we find $-0.12 \le \Delta\kappa_Z \le 0.29$ $(\lambda_Z=0)$ at the 95% C.L. These are the most restrictive limits on the $WWZ$ couplings available to date.

We present results of searches for diphoton resonances produced both inclusively and also in association with a vector boson (W or Z) using 100 $pb^{-1}$ of $p\bar{p}$ collisions using the CDF detector. We set upper limits on the product of cross section times branching ratio for both $p\bar{p} \to \gamma \gamma + X$ and $p \bar{p} \to \gamma \gamma + W/Z$. Comparing the inclusive production to the expectations from heavy sgoldstinos we derive limits on the supersymmetry-breaking scale $\sqrt{F}$ in the TeV range, depending on the sgoldstino mass and the choice of other parameters. Also, using a NLO prediction for the associated production of a Higgs boson with a W or Z boson, we set an upper limit on the branching ratio for $H \to \gamma \gamma$. Finally, we set a lower limit on the mass of a 'bosophilic' Higgs boson (e.g. one which couples only to $\gamma, W,$ and $Z$ bosons with standard model couplings) of 82 GeV/$c^2$ at 95% confidence level.

We present a measurement of the W+W- production cross section using 184/pb of ppbar collisions at a center-of-mass energy of 1.96 TeV collected with the Collider Detector at Fermilab. Using the dilepton decay channel W+W- -> l+l-vvbar, where the charged leptons can be either electrons or muons, we find 17 candidate events compared to an expected background of 5.0+2.2-0.8 events. The resulting W+W- production cross section measurement of sigma(ppbar -> W+W-) = 14.6 +5.8 -5.1 (stat) +1.8 -3.0 (syst) +-0.9 (lum) pb agrees well with the Standard Model expectation.

The Standard Model predictions for $W\gamma$ and $Z\gamma$ production are tested using an integrated luminosity of 200 pb$^{-1}$ of \ppbar collision data collected at the Collider Detector at Fermilab. The cross sections are measured selecting leptonic decays of the $W$ and $Z$ bosons, and photons with transverse energy $E_T>7$ GeV that are well separated from leptons. The production cross sections and kinematic distributions for the $W\gamma$ and $Z\gamma$ are compared to SM predictions.

Measurements of inclusive W and Z boson production cross sections in pp collisions at sqrt(s)=7 TeV are presented, based on 2.9 inverse picobarns of data recorded by the CMS detector at the LHC. The measurements, performed in the electron and muon decay channels, are combined to give sigma(pp to WX) times B(W to muon or electron + neutrino) = 9.95 \pm 0.07(stat.) \pm 0.28(syst.) \pm 1.09(lumi.) nb and sigma(pp to ZX) times B(Z to oppositely charged muon or electron pairs) = 0.931 \pm 0.026(stat.) \pm 0.023(syst.) \pm 0.102(lumi.) nb. Theoretical predictions, calculated at the next-to-next-to-leading order in QCD using recent parton distribution functions, are in agreement with the measured cross sections. Ratios of cross sections, which incur an experimental systematic uncertainty of less than 4%, are also reported.

A measurement of WW production in pp collisions at sqrt(s) = 7 TeV and a search for the Higgs boson are reported. The WW candidates are selected in events with two leptons, either electrons or muons. The measurement is performed using LHC data recorded with the CMS detector, corresponding to an integrated luminosity of 36 inverse picobarns. The pp to WW cross section is measured to be 41.1 +/- 15.3 (stat) +/- 5.8 (syst) +/- 4.5 (lumi) pb, consistent with the standard model prediction. Limits on WW gamma and WWZ anomalous triple gauge couplings are set. The search for the standard model Higgs boson in the WW decay mode does not reveal any evidence of excess above backgrounds. Limits are set on the production of the Higgs boson in the context of the standard model and in the presence of a sequential fourth family of fermions with high masses. In the latter context, a Higgs boson with mass between 144 and 207 GeV is ruled out at 95% confidence level.

A study of WZ production in proton-proton collisions at sqrt(s) = 7 TeV is presented using data corresponding to an integrated luminosity of 4.6 fb^-1 collected with the ATLAS detector at the Large Hadron Collider in 2011. In total, 317 candidates, with a background expectation of 68+/-10 events, are observed in double-leptonic decay final states with electrons, muons and missing transverse momentum. The total cross-section is determined to be sigma_WZ(tot) = 19.0+1.4/-1.3(stat.)+/-0.9(syst.)+/-0.4(lumi.) pb, consistent with the Standard Model expectation of 17.6+1.1/-1.0 pb. Limits on anomalous triple gauge boson couplings are derived using the transverse momentum spectrum of Z bosons in the selected events. The cross section is also presented as a function of Z boson transverse momentum and diboson invariant mass.

This Letter reports a search for a heavy particle that decays to WW using events produced in pp collisions at sqrt(s) = 7 TeV. The data were recorded in 2011 by the ATLAS detector and correspond to an integrated luminosity of 4.7 fb-1. WW to l nu l' nu'(l, l' = e or mu) final states are considered and the distribution of the transverse mass of the WW candidates is found to be consistent with Standard Model expectations. Upper limits on the production cross section times branching ratio into W boson pairs are set for Randall-Sundrum and bulk Randall-Sundrum gravitons, which result in observed 95% CL lower limits on the masses of the two particles of 1.23 TeV and 0.84 TeV, respectively.

This paper presents a measurement of the W^+W^- production cross section in pp collisions at sqrt{s}=7 TeV. The leptonic decay channels are analyzed using data corresponding to an integrated 4.6 fb-1 collected with the ATLAS detector at the Large Hadron Collider. The W^+W^- production cross section sigma(pp -> W^+W^-+X) is measured to be 51.9 +- 2.0 (stat) +- 3.9 (syst) +- 2.0 (lumi) pb, compatible with the Standard Model prediction of 44.7 +2.1 -1.9 pb. A measurement of the normalized fiducial cross section as a function of the leading lepton transverse momentum is also presented. The reconstructed transverse momentum distribution of the leading lepton is used to extract limits on anomalous WWZ and WWgamma couplings.

Measurements are presented of W gamma gamma and Z gamma gamma production in proton-proton collisions. Fiducial cross sections are reported based on a data sample corresponding to an integrated luminosity of 19.4 inverse femtobarns collected with the CMS detector at a center-of-mass energy of 8 TeV. Signal is identified through the W to l nu and Z to ll decay modes, where l is a muon or an electron. The production of W gamma gamma and Z gamma gamma, measured with significances of 2.6 and 5.9 standard deviations, respectively, is consistent with standard model predictions. In addition, limits on anomalous quartic gauge couplings in W gamma gamma production are determined in the context of a dimension-8 effective field theory.

The W boson helicity fractions from top quark decays in t t-bar events are measured using data from proton-proton collisions at a centre-of-mass energy of 8 TeV. The data were collected in 2012 with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.8 inverse femtobarns. Events are reconstructed with either one muon or one electron, along with four jets in the final state, with two of the jets being identified as originating from b quarks. The measured helicity fractions from both channels are combined, yielding F[0] = 0.681 +/- 0.012 (stat) +/- 0.023 (syst), F[L] = 0.323 +/- 0.008 (stat) +/- 0.014 (syst), and F[R] = -0.004 +/- 0.005 (stat) +/- 0.014 (syst) for the longitudinal, left-, and right-handed components of the helicity, respectively. These measurements of the W boson helicity fractions are the most accurate to date and they agree with the predictions from the standard model.

The production cross section of a W boson in association with two b jets is measured using a sample of proton-proton collisions at sqrt(s) = 8 TeV collected by the CMS experiment at the CERN LHC. The data sample corresponds to an integrated luminosity of 19.8 inverse femtobarns. The W bosons are reconstructed via their leptonic decays, W to l nu, where l = mu or e. The fiducial region studied contains exactly one lepton with transverse momentum pt[l] > 30 GeV and pseudorapidity abs(eta[l]) < 2.1, with exactly two b jets with pt > 25 GeV and abs(eta) < 2.4 and no other jets with pt > 25 GeV and abs(eta) < 4.7. The cross section is measured to be sigma(pp to W (l nu)+ bb-bar) = 0.64 +/- 0.03 (stat) +/- 0.10 (syst) +/- 0.06 (theo) +/- 0.02 (lumi) pb, in agreement with standard model predictions.

Differential cross sections for a W boson produced in association with jets are measured in a data sample of proton-proton collisions at a center-of-mass energy of 8 TeV recorded with the CMS detector and corresponding to an integrated luminosity of 19.6 inverse femtobarns. The W bosons are identified through their decay mode W to mu nu. The cross sections are reported as functions of jet multiplicity, transverse momenta, and the scalar sum of jet transverse momenta (HT) for different jet multiplicities. Distributions of the angular correlations between the jets and the muon are examined, as well as the average number of jets as a function of HT and as a function of angular variables. The measured differential cross sections are compared with tree-level and higher-order recent event generators, as well as next-to-leading-order and next-to-next-to-leading-order theoretical predictions. The agreement of the generators with the measurements builds confidence in their use for the simulation of W+jets background processes in searches for new physics at the LHC.

A search for exclusive or quasi-exclusive gamma gamma to W+W- production, via pp to p(*) W+W- p(*) to p(*) mu+/- e-/+ at sqrt(s) = 8 TeV, is reported using data corresponding to an integrated luminosity of 19.7 inverse femtobarns. Events are selected by requiring the presence of an electron-muon pair with large transverse momentum pt(mu+/- e-/+) > 30 GeV, and no associated charged particles detected from the same vertex. The 8 TeV results are combined with the previous 7 TeV results (obtained for 5.05 inverse femtobarns of data). In the signal region, 13 (2) events are observed over an expected background of 3.9 +/- 0.6 (0.84 +/-0.15) events for 8 (7) TeV, resulting in a combined excess of 3.4 standard deviations over the background-only hypothesis. The observed yields and kinematic distributions are compatible with the standard model prediction for exclusive and quasi-exclusive gamma gamma to W+W- production. Upper limits on the anomalous quartic gauge coupling operators a[W;0,C] (dimension-6) and f[M0,1,2,3] (dimension-8), the most stringent to date, are derived from the measured dilepton transverse momentum spectrum.

The differential cross section and charge asymmetry for inclusive pp to W + X to mu + neutrino + X production at sqrt(s) = 8 TeV are measured as a function of muon pseudorapidity. The data sample corresponds to an integrated luminosity of 18.8 inverse femtobarns recorded with the CMS detector at the LHC. These results provide important constraints on the parton distribution functions of the proton in the range of the Bjorken scaling variable x from 10E-3 to 10E-1.

A search for a heavy Higgs boson in the H to WW and H to ZZ decay channels is reported. The search is based upon proton-proton collision data samples corresponding to an integrated luminosity of up to 5.1 inverse femtobarns at sqrt(s) = 7 TeV and up to 19.7 inverse femtobarns at sqrt(s) = 8 TeV, recorded by the CMS experiment at the CERN LHC. Several final states of the H to WW and H to ZZ decays are analyzed. The combined upper limit at the 95% confidence level on the product of the cross section and branching fraction exclude a Higgs boson with standard model-like couplings and decays in the range 145 < m[H] < 1000 GeV. We also interpret the results in the context of an electroweak singlet extension of the standard model.