No abstract

We give a detailed description of the measurement of the W boson mass, MW , performed on an integrated luminosity of 4.3 fb −1 , which is based on similar techniques as used for our previous measurement done on an independent data set of 1 fb −1 of data. The data were collected using the D0 detector at the Fermilab Tevatron Collider. This data set yields 1.68 × 10 6 W → eν candidate events. We measure the mass using the transverse mass, electron transverse momentum, and missing transverse energy distributions. The MW measurements using the transverse mass and the electron transverse momentum distributions are the most precise of these three and are combined to give MW = 80.367 ± 0.013 (stat) ± 0.022 (syst) GeV = 80.367 ± 0.026 GeV. When combined with our earlier measurement on 1 fb −1 of data, we obtain MW = 80.375 ± 0.023 GeV.

We summarize and combine direct measurements of the mass of the W boson in √ s = 1.96 TeV proton-antiproton collision data collected by CDF and D0 experiments at the Fermilab Tevatron Collider. Earlier measurements from CDF and D0 are combined with the two latest, more precise measurements: a CDF measurement in the electron and muon channels using data corresponding to 2.2 fb −1 of integrated luminosity, and a D0 measurement in the electron channel using data corresponding to 4.3 fb −1 of integrated luminosity. The resulting Tevatron average for the mass of the W boson is MW = 80 387 ± 16 MeV. Including measurements obtained in electron-positron collisions at LEP yields the most precise value of MW = 80 385 ± 15 MeV.

We combine searches by the CDF and D0 Collaborations for the associated production of a Higgs boson with a W or Z boson and subsequent decay of the Higgs boson to a bottom-antibottom quark pair. The data, originating from Fermilab Tevatron pp collisions at √ s = 1.96 TeV, correspond to integrated luminosities of up to 9.7 fb −1 . The searches are conducted for a Higgs boson with mass in the range 100-150 GeV/c 2 . We observe an excess of events in the data compared with the background predictions, which is most significant in the mass range between 120 and 135 GeV/c 2 . The largest local significance is 3.3 standard deviations, corresponding to a global significance of 3.1 standard deviations. We interpret this as evidence for the presence of a new particle consistent with the standard model Higgs boson, which is produced in association with a weak vector boson and decays to a bottom-antibottom quark pair.

We perform a combination of searches for standard model Higgs boson production in p p collisions recorded by the D0 detector at the Fermilab Tevatron Collider at a center of mass energy of ffiffi ffi s p ¼ 1:96 TeV. The different production and decay channels have been analyzed separately, with integrated luminosities of up to 9:7 fb À1 and for Higgs boson masses 90 M H 200 GeV. We combine these final states to achieve optimal sensitivity to the production of the Higgs boson. We also interpret the combination in terms of models with a fourth generation of fermions, and models with suppressed Higgs boson couplings to fermions. The result excludes a standard model Higgs boson at 95% C.L. in the ranges 90 < M H < 101 GeV and 157 < M H < 178 GeV, with an expected exclusion of 155 < M H < 175 GeV. In the range 120 < M H < 145 GeV, the data exhibit an excess over the expected background of up to 2 standard deviations, consistent with the presence of a standard model Higgs boson of mass 125 GeV.