Simultaneous measurement of the ratio R = B(t -> Wb)/B(t -> Wq) and the top-quark pair production cross section with the D0 detector at root s=1.96 TeV

We present the first simultaneous measurement of the ratio of branching fractions, R = B(t --> Wb)/B(t --> Wq), with q being a d, s, or b quark, and the top-quark pair production cross section sigma(t (t) over bar) in the lepton plus jets channel using 0.9 fb(-1) of p (p) over bar collision data at root s = 1.96 TeV collected with the D0 detector. We extract R and sigma(t (t) over bar) by analyzing samples of events with 0, 1, and >= 2 identified b jets. We measure R = 0.97(-0.08)(+0.09) (stat + syst) and sigma(t (t) over bar) = 8.18(-0.84)(+0.90) (stat + syst) +/- 0.50(lumi) pb, in agreement with the standard model prediction.

Measurement of the Z gamma -> nu(nu)over-bar gamma Production Cross Section and Limits on Anomalous ZZ gamma and Z gamma gamma Couplings in p(p)over-bar Collisions at root s=1.96 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Search for ZH -> l(+)l(-) b(b)over-bar Production in 4.2 fb(-1) of p(p)over-bar Collisions at root s=1.96 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Search for the Standard Model Higgs Boson in the Missing Energy and Acoplanar b-Jet Topology at root s=1.96 TeV

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Measurement of the Semileptonic Branching Ratio of Bs(0) to an Orbitally Excited D-s** State: Br(Bs(0) -> Ds1(-)(2536)mu(+)nu X)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Search for Associated W and Higgs Boson Production in p(p)over-bar Collisions at root s=1.96 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Search for Anomalous Top-Quark Couplings with the D0 Detector

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Search for the Associated Production of a b Quark and a Neutral Supersymmetric Higgs Boson that Decays into tau Pairs

We report results from a search for production of a neutral Higgs boson in association with a b quark. We search for Higgs decays to tau pairs with one tau subsequently decaying to a muon and the other to hadrons. The data correspond to 2: 7 fb(-1) of p (p) over bar collisions recorded by the D0 detector at.. root s = 1.96 TeV. The data are found to be consistent with background predictions. The result allows us to exclude a significant region of parameter space of the minimal supersymmetric model.

Search for CP violation in B-s(0) -> mu(+) D-s(-) X decays in p(p)over-bar collisions at root s=1.96 TeV

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Model-independent measurement of the W-boson helicity in top-quark decays at D0

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 (t) over bar events in the dilepton and lepton plus jets channels collected by the D0 detector at the Fermilab Tevatron p (p) over bar 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 cos theta(*) distribution finds that the fraction of longitudinal W bosons f(0)=0.425 +/- 0.166(stat)+/- 0.102(syst) and the fraction of right-handed W bosons f(+)=0.119 +/- 0.090(stat)+/- 0.053(syst), which is consistent at the 30% C.L. with the standard model.

Observation and properties of the orbitally excited B-s2* meson

We report the direct observation of the excited L=1 state B-s2* in fully reconstructed decays to B+K-. The mass of the B-s2* meson is measured to be 5839.6 +/- 1.1(stat)+/- 0.7(syst) MeV/c(2), and its production rate relative to the B+ meson is measured to be [1.15 +/- 0.23(stat)+/- 0.13(syst)]%.

Measurement of B-s(0) Mixing Parameters from the Flavor-Tagged Decay B-s(0)-> J/psi phi

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Search for Large Extra Spatial Dimensions in the Dielectron and Diphoton Channels in p(p)over-bar Collisions at root s=1.96 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Observation of the Doubly Strange b Baryon Omega(-)(b)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Evidence of WW and WZ Production with lepton plus jets Final States in pp Collisions at root s=1.96 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)