Data recorded by the D0 experiment at the Fermilab Tevatron Collider are analyzed to search for neutral Higgs bosons produced in association with b quarks. The search is performed in the ...three-b-quark channel using multijet-triggered events corresponding to an integrated luminosity of 5.2 fbsuper-1. In the absence of any significant excess above background, limits are set on the cross section multiplied by the branching ratio in the Higgs boson mass range 90 to 300 GeV, extending the excluded regions in the parameter space of the minimal supersymmetric standard model.
We present a search for associated production of Higgs and W bosons in inline image collisions at a center of mass energy of inline image in 5.3 fbsuper-1 of integrated luminosity recorded by the D0 ...experiment. Multivariate analysis techniques are applied to events containing one lepton, an imbalance in transverse energy, and one or two b-tagged jets to discriminate a potential WH signal from Standard Model backgrounds. We observe good agreement between data and expected backgrounds, and set an upper limit of 4.5 (at 95% confidence level and for m sub(H=115 GeV) on the ratio of the WH cross section multiplied by the branching fraction of inline image to its Standard Model prediction, which is consistent with an expected limit of 4.8.)
We present a search for flavor changing neutral currents via quark-gluon couplings in a sample of single top quark final states corresponding to 2.3 fbsuper-1 of integrated luminosity collected with ...the D0 detector at the Fermilab Tevatron Collider. We select events containing a single top quark candidates with an additional jet, and obtain separation between signal and background using Bayesian neural networks. We find consistency between background expectation and observed data, and set limits on flavor changing neutral current gluon couplings of the top quark to up quarks (tgu) and charm quarks (tgc). The cross section limits at the 95% C.L. are sigma sub(tgu0.20 pb and sigma) sub(t)gc0.27 pb. These correspond to limits on the top quark decay branching fractions of inline imageinline image and inline imageinline image.
Background
Overweight adults are at increased risk for cardiovascular disease and vitamin D deficiency, whereas an important feature to vitamin D physiology is its sex dependence. The aim of this ...study was to examine whether vitamin D status improvement exerts a sexually dimorphic effect on serum proteins associated with cardiovascular risk among overweight adults.
Materials and methods
Unprocessed serum from age‐ and BMI‐matched men (n = 26) and premenopausal women (n = 24) with vitamin D deficiency and after they achieved sufficiency through a 12‐month nutritional intervention was analysed using our previously published depletion‐free quantitative proteomics method. Key findings were verified with ELISA. Differentially expressed proteins were subjected to in silico bioinformatics assessment using principal component analysis, hierarchical clustering and Metacore™ pathway analysis. All mass spectrometry proteomic data are available via ProteomeXchange (identifier: PXD003663).
Results
A total of 282 proteins were differentially expressed after the intervention between men and women (P‐value ≤ 0·05), in which the blood coagulation pathway was significantly enriched. In agreement with the proteomics findings, ELISA measurements showed vitamin K‐dependent protein C, von Willebrand factor, fibrinogen gamma chain and multimerin‐1 proteins, of relevance to blood coagulation, to be differentially affected (P‐value ≤ 0·05) between sexes after vitamin D status correction.
Conclusions
This study identified novel protein‐level molecular indicators on the sexually dimorphic effect of vitamin D status correction associated with blood coagulation among overweight adults. These sex‐mediated vitamin D effects should be factored in the design and interpretation of vitamin D observational and interventional studies testing cardiometabolic outcomes.
Measurement of the W boson mass Alverson, G; Andeen, T; Anzelc, M S ...
Physical review letters,
10/2009, Letnik:
103, Številka:
14
Journal Article
Recenzirano
Odprti dostop
We present a measurement of the W boson mass in W-->e(nu) decays using 1 fb-1 of data collected with the D0 detector during Run II of the Fermilab Tevatron collider. With a sample of 499830 W-->e(nu) ...candidate events, we measure M(W)=80.401+/-0.043 GeV. This is the most precise measurement from a single experiment.
We present the first measurement of dijet angular distributions in pp collisions at s=1.96 TeV at the Fermilab Tevatron Collider. The measurement is based on a dataset corresponding to an integrated ...luminosity of 0.7 fb(-1) collected with the D0 detector. Dijet angular distributions have been measured over a range of dijet masses, from 0.25 TeV to above 1.1 TeV. The data are in good agreement with the predictions of perturbative QCD and are used to constrain new physics models including quark compositeness, large extra dimensions, and TeV(-1) scale extra dimensions. For all models considered, we set the most stringent direct limits to date.
We report the results of a search for associated production of charginos and neutralinos using a data set corresponding to an integrated luminosity of 2.3 fb(-1) collected with the Demptyset ...experiment during Run II of the Tevatron proton-antiproton collider. Final states containing three charged leptons and missing transverse energy are probed for a signal from supersymmetry with four dedicated trilepton event selections. No evidence for a signal is observed, and we set limits on the product of production cross section and leptonic branching fraction. Within minimal supergravity, these limits translate into bounds on m(0) and m(1/2) that are well beyond existing limits.
We search for long-lived charged massive particles using 1.1 fb;{-1} of data collected by the D0 detector at the Fermilab Tevatron ppover Collider. Time-of-flight information is used to search for ...pair produced long-lived tau sleptons, gauginolike charginos, and Higgsino-like charginos. We find no evidence of a signal and set 95% C.L. cross section upper limits for staus, which vary from 0.31 to 0.04 pb for stau masses between 60 and 300 GeV. We also set lower mass limits of 206 GeV (171 GeV) for pair produced charged gauginos (Higgsinos).
We describe a search for production of a charged Higgs boson, qqover ;{'}-->H;{+}, reconstructed in the tbover final state in the mass range 180< or =M_{H;{+}}< or =300 GeV. The search was ...undertaken at the Fermilab Tevatron collider with a center-of-mass energy sqrts=1.96 TeV and uses 0.9 fb;{-1} of data collected with the D0 detector. We find no evidence for charged Higgs boson production and set upper limits on the production cross section in the types I, II, and III two-Higgs-doublet models (2HDMs). An excluded region in the (M_{H;{+}}, tanbeta) plane for type I 2HDM is presented.
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