Search for Resonant Diphoton Production with the D0 Detector

This is the publisher's version, also available electronically from http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.102.231801.We present a search for a narrow resonance in the inclusive diphoton final state using ∼2.7  fb(−1) of data collected with the D0 detector at the Fermilab Tevatron pp-bar Collider. We observe good agreement between the data and the background prediction, and set the first 95% C.L. upper limits on the production cross section times the branching ratio for decay into a pair of photons for resonance masses between 100 and 150 GeV. This search is also interpreted in the context of several models of electroweak symmetry breaking with a Higgs boson decaying into two photons

Search for Charged Higgs Bosons Decaying into Top and Bottom Quarks in pp-bar Collisions

This is the publisher's version, also available electronically from http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.102.191802.We describe a search for production of a charged Higgs boson, qq-bar′→H(+), reconstructed in the tb-bar final state in the mass range 180≤M(H+)≤300  GeV. The search was undertaken at the Fermilab Tevatron collider with a center-of-mass energy s√=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+,) tanβ) plane for type I 2HDM is presented

Measurement of the tt-bar cross section using high-multiplicity jet events

This is the publisher's version, also available electronically from http://journals.aps.org/prd/abstract/10.1103/PhysRevD.82.032002.We present a measurement of the tt-bar cross section using high-multiplicity jet events produced in pp-bar collisions at s√=1.96  TeV. These data were recorded at the Fermilab Tevatron Collider with the D0 detector. Events with at least six jets, two of them identified as b jets, were selected from a 1  fb(−1) data set. The measured cross section, assuming a top quark mass of 175  GeV/c2, is 6.9±2.0  pb, in agreement with theoretical expectations

Search for charged Higgs bosons in top quark decays

We present a search for charged Higgs bosons in top quark decays. We analyze the e+jetse+jets, μ+jetsμ+jets, ee, eμ, μμ, τe and τμ final states from top quark pair production events, using data from about 1 fb^(−1) of integrated luminosity recorded by the DØ experiment at the Fermilab Tevatron Collider. We consider different scenarios of possible charged Higgs boson decays, one where the charged Higgs boson decays purely hadronically into a charm and a strange quark, another where it decays into a τ lepton and a τ neutrino and a third one where both decays appear. We extract limits on the branching ratio B(t→H+b)B(t→H+b) for all these models. We use two methods, one where the View the MathML ttbar production cross section is fixed, and one where the cross section is fitted simultaneously with B(t→H+b)B(t→H+b). Based on the extracted limits, we exclude regions in the charged Higgs boson mass and tanβtanβ parameter space for different scenarios of the minimal supersymmetric standard model

Search for associated production of charginos and neutralinos in the trilepton final state using 2.3 fb^(−1) of data

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 DØ 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 m0m0 and m1/2m1/2 that are well beyond existing limits

Observation of Single Top-Quark Production

This is the publisher's version, also available electronically from http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.103.092001

Cancer Survivors' Health Worries and Associations with Lifestyle Practices

This study examined among recently diagnosed breast and prostate cancer survivors (N = 678) associations between worry about a future diagnosis of heart disease or cancer and hypothetical and actual adherence to exercise and dietary guidelines. Greater worry about future illness was reported under the hypothetical scenario of nonadherence to guidelines relative to the scenario of adherence. Worry about potential heart disease was associated with actual adherence to guidelines, whereas worry about a potential cancer diagnosis was not. Findings suggest that the motivational properties of worry should be considered when developing interventions to reduce heart disease risk among cancer survivors

Measurement of the W boson mass

We present a measurement of the W boson mass in W -> ev 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 -> ev candidate events, we measure M_W = 80.401 +- 0.043 GeV. This is the most precise measurement from a single experiment.Comment: As published in PR

Measurement of the t-channel single top quark production cross section

The D0 collaboration reports direct evidence for electroweak production of single top quarks through the t-channel exchange of a virtual W boson. This is the first analysis to isolate an individual single top quark production channel. We select events containing an isolated electron or muon, missing transverse energy, and two, three or four jets from 2.3 fb^-1 of ppbar collisions at the Fermilab Tevatron Collider. One or two of the jets are identified as containing a b hadron. We combine three multivariate techniques optimized for the t-channel process to measure the t- and s-channel cross sections simultaneously. We measure cross sections of 3.14 +0.94 -0.80 pb for the t-channel and 1.05 +-0.81 pb for the s-channel. The measured t-channel result is found to have a significance of 4.8 standard deviations and is consistent with the standard model prediction.Comment: 7 pages, 6 figure