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 fb−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.
A fully reconstructed Bc --> Jpsi Pi signal is observed with the D0 detector at the Fermilab Tevatron p-pbar collider. Using 1.3 inverse femtobarns of integrated luminosity, the signal is extracted ...with a significance more than five standard deviations above background. The measured Bc meson mass is 6300 (+-) 14 (stat) (+-) 5 (sys) MeV/cc
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 pp¯ 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 3.14−0.80+0.94 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.
We present a search for a neutral particle, pair produced in pp collisions at root s=1.96 TeV, which decays into two muons and lives long enough to travel at least 5 cm before decaying. The analysis ...uses approximate to 380 pb(-1) of data recorded with the D0 detector. The background is estimated to be about one event. No candidates are observed, and limits are set on the pair-production cross section times branching fraction into dimuons + X for such particles. For a mass of 10 GeV and lifetime of 4x10(-11) s, we exclude values greater than 0.14 pb (95% C.L.). These results are used to limit the interpretation of NuTeV's excess of dimuon events.
A search for gaugino pair production with a trilepton signature in the framework of R-parity violating supersymmetry via the couplings; lambda(121), lambda(122), or lambda(133) is presented. The ...data, corresponding to an integrated luminosity of L approximate to 360 pb(-1), were collected from April 2002 to August 2004 with the D0 detector at the Fermilab Tevatron Collider, at a center-of-mass energy of root s = 1.96 TeV. This analysis considers final states with three charged leptons with the flavor combinations eel, mu mu l, and ee tau (l = e or mu). No evidence for supersymmetry is found and limits at the 95% confidence level are set on the gaugino pair production cross section and lower bounds on the masses of the lightest neutralino and chargino are derived in two supersymmetric models.
We report the results of a search for pair production of scalar bottom quarks (b˜1) and scalar third-generation leptoquarks (LQ3) in 5.2 fb−1 of pp¯ collisions at the D0 experiment of the Fermilab ...Tevatron Collider. Scalar bottom quarks are assumed to decay to a neutralino (χ˜10) and a b quark, and we set 95% C.L. lower limits on their production in the (mb˜1, mχ˜10) mass plane such as mb˜1>247 GeV for mχ˜10=0 and mχ˜10>110 GeV for 160<mb˜1<200 GeV. The leptoquarks are assumed to decay to a tau neutrino and a b quark, and we set a 95% C.L. lower limit of 247 GeV on the mass of a charge-1/3 third-generation scalar leptoquark.
The D0 Silicon Microstrip Tracker Ahmed, S.N.; Aoki, M.; Åsman, B. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2011, Letnik:
634, Številka:
1
Journal Article
Recenzirano
Odprti dostop
This paper describes the mechanical design, the readout chain, the production, testing and the installation of the Silicon Microstrip Tracker of the D0 experiment at the Fermilab Tevatron collider. ...In addition, we describe the performance and operational experience of the detector during the experiment data collection between 2001 and 2010.
We present new direct constraints on a general Wtb interaction using data corresponding to an integrated luminosity of 5.4 fb−1 collected by the D0 detector at the Tevatron pp¯ collider. The standard ...model provides a purely left-handed vector coupling at the Wtb vertex, while the most general, lowest dimension Lagrangian allows right-handed vector and left- or right-handed tensor couplings as well. We obtain precise limits on these anomalous couplings by comparing the data to the expectations from different assumptions on the Wtb coupling.
This Letter describes measurements of inclusive W(→eν)+n jet cross sections (n=1–4), presented as total inclusive cross sections and differentially in the nth jet transverse momentum. The ...measurements are made using data corresponding to an integrated luminosity of 4.2 fb−1 collected by the D0 detector at the Fermilab Tevatron Collider, and achieve considerably smaller uncertainties on W+jets production cross sections than previous measurements. The measurements are compared to next-to-leading order perturbative QCD (pQCD) calculations in the n=1–3 jet multiplicity bins and to leading order pQCD calculations in the 4-jet bin. The measurements are generally in agreement with pQCD calculations, although certain regions of phase space are identified where these predictions could better match the data.
We describe a search for the Standard Model Higgs boson with a mass of 105 GeV/c(2) to 145 GeV/c(2) in data corresponding to an integrated luminosity of approximately 450 pb(-1) collected with the D ...phi detector at the Fermilab Tevatron p (p) over bar collider at a center-of-mass energy of 1.96 TeV. The Higgs boson is required to be produced in association with a Z boson, and the Z boson is required to decay to either electrons or muons with the Higgs boson decaying to a b (b) over bar pair. The data are well described by the expected background, leading to 95% confidence level cross section upper limits sigma (p (p) over bar -> ZH) x B(H -> b (b) over bar) in the range of 3.1 pb to 4.4 pb.
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