Precise measurement of the W-boson mass with the CDF II detector

We have measured the W-boson mass MW using data corresponding to 2.2/fb of integrated luminosity collected in proton-antiproton collisions at 1.96 TeV with the CDF II detector at the Fermilab Tevatron collider. Samples consisting of 470126 W->enu candidates and 624708 W->munu candidates yield the measurement MW = 80387 +- 12 (stat) +- 15 (syst) = 80387 +- 19 MeV. This is the most precise measurement of the W-boson mass to date and significantly exceeds the precision of all previous measurements combined

Measurement of the Ratio of b Quark Production Cross Sections in Antiproton-Proton Collisions at 630 GeV and 1800 GeV

We report a measurement of the ratio of the bottom quark production cross section in antiproton-proton collisions at 630 GeV to 1800 GeV using bottom quarks with transverse momenta greater than 10.75 GeV identified through their semileptonic decays and long lifetimes. The measured ratio sigma(630)/sigma(1800) = 0.171 +/- .024 +/- .012 is in good agreement with next-to-leading order (NLO) quantum chromodynamics (QCD)

Search for a Low-Mass Standard Model Higgs Boson in the tautau Decay Channel in pp[over ] Collisions at sqrt[s]=1.96TeV.

We report on a search for the standard model Higgs boson decaying into pairs of tau leptons in pp[over ] collisions produced by the Tevatron at sqrt[s]=1.96TeV. The analyzed data sample was recorded by the CDFII detector and corresponds to an integrated luminosity of 6.0fb^{-1}. The search is performed in the final state with one tau decaying leptonically and the second one identified through its semihadronic decay. Since no significant excess is observed, a 95% credibility level upper limit on the production cross section times branching ratio to the tautau final state is set for hypothetical Higgs boson masses between 100 and 150GeV/c^{2}. For a Higgs boson of 120GeV/c^{2} the observed (expected) limit is 14.6 (15.3) the predicted value

Search for WZ plus ZZ production with missing transverse energy plus jets with b enhancement at root s=1.96 TeV

Diboson production (WW + WZ + ZZ) has been observed at the Tevatron in hadronic decay modes dominated by the WW process. This paper describes the measurement of the cross section of WZ and ZZ events in final states with large (sic)(T) and using b-jet identification as a tool to suppress WW contributions. Because of the limited energy resolution, we cannot distinguish between partially hadronic decays of WZ and ZZ, and we measure the sum of these processes. The number of signal events is extracted using a simultaneous fit to the invariant mass distribution of the two jets for events with two b-jet candidates and events with fewer than two b-jet candidates. We measure a cross section sigma(p (p) over bar -> WZ, ZZ) = 5.8(3.0)(+3.6) pb, in agreement with the standard model

Search for a Higgs Boson in the Diphoton Final State in p(p)over-bar Collisions at root s=1: 96 TeV

A search for a narrow Higgs boson resonance in the diphoton mass spectrum is presented based on data corresponding to 7.0 fb(-1) of integrated luminosity from p (p) over bar collisions at root s = 1: 96 TeV collected by the CDF experiment. No evidence of such a resonance is observed, and upper limits are set on the cross section times branching ratio of the resonant state as a function of Higgs boson mass. The limits are interpreted in the context of the standard model and one fermiophobic benchmark model where the data exclude fermiophobic Higgs bosons with masses below 114 GeV/c(2) at a 95% Bayesian credibility level

Comparison of three-jet events in p(p)over-bar collisions at root s=1.8 TeV to predictions from a next-to-leading order QCD calculation

The properties of three-jet events with total transverse energy greater than 320 GeV and individual jet energy greater than 20 GeV have been analyzed and compared to absolute predictions from a next-to-leading order (NLO) perturbative QCD calculation. These data, of integrated luminosity 86 pb -1, were recorded by the CDF Experiment for pp collisions at √s = 1.8 TeV This study tests a model of higher order QCD processes that result in gluon emission and may give some indication of the magnitude of the contribution of processes higher than NLO. The total cross section is measured to be 466 ± 3(stat.)-70+207(syst.) pb. The differential cross section is furthermore measured for all kinematically accessible regions of the Dalitz plane, including those for which the theoretical prediction is unreliable. While the measured cross section is consistent with the theoretical prediction in magnitude, the two differ somewhat in shape in the Dalitz plane. © 2005 The American Physical Society