Measurement of the inclusive jet cross section in pp̄ collisions at s=1.96TeV
Physical Review Letters 101:6 (2008)
Abstract:
We report on a measurement of the inclusive jet cross section in pp̄ collisions at a center-of-mass energy s=1.96TeV using data collected by the D0 experiment at the Fermilab Tevatron Collider corresponding to an integrated luminosity of 0.70fb-1. The data cover jet transverse momenta from 50 to 600 GeV and jet rapidities in the range -2.4 to 2.4. Detailed studies of correlations between systematic uncertainties in transverse momentum and rapidity are presented, and the cross section measurements are found to be in good agreement with next-to-leading order QCD calculations. © 2008 The American Physical Society.Search for decay of a fermiophobic Higgs boson hf-->gammagamma with the D0 detector at sqrt s=1.96 TeV.
Phys Rev Lett 101:5 (2008) 051801
Abstract:
We report the results of a search for a narrow resonance decaying into two photons in 1.1 fb;{-1} of data collected by the D0 experiment at the Fermilab Tevatron Collider during the period 2002-2006. We find no evidence for such a resonance and set a lower limit on the mass of a fermiophobic Higgs boson of m_{h_{f}}>100 GeV at the 95% C.L. This exclusion limit exceeds those obtained in previous searches at the Fermilab Tevatron and covers a significant region of the parameter space B(h_{f}-->gammagamma) vs m_{h_{f}} which was not accessible at the CERN Large Electron-Positron Collider.Search for decay of a fermiophobic higgs boson hf→ y y with the D0 detector at s=1.96a TeV
Physical Review Letters 101:5 (2008)
Abstract:
We report the results of a search for a narrow resonance decaying into two photons in 1.1fb-1 of data collected by the D0 experiment at the Fermilab Tevatron Collider during the period 2002"2006. We find no evidence for such a resonance and set a lower limit on the mass of a fermiophobic Higgs boson of mhf>100GeV at the 95% C.L. This exclusion limit exceeds those obtained in previous searches at the Fermilab Tevatron and covers a significant region of the parameter space B(hf→I I ) vs mhf which was not accessible at the CERN Large Electron-Positron Collider. © 2008 The American Physical Society.Evidence for production of single top quarks
Physical Review D - Particles, Fields, Gravitation and Cosmology 78:1 (2008)
Abstract:
We present first evidence for the production of single top quarks in the D0 detector at the Fermilab Tevatron pp̄ collider. The standard model predicts that the electroweak interaction can produce a top quark together with an antibottom quark or light quark, without the antiparticle top-quark partner that is always produced from strong-coupling processes. Top quarks were first observed in pair production in 1995, and since then, single top-quark production has been searched for in ever larger data sets. In this analysis, we select events from a 0.9fb-1 data set that have an electron or muon and missing transverse energy from the decay of a W boson from the top-quark decay, and two, three, or four jets, with one or two of the jets identified as originating from a b hadron decay. The selected events are mostly backgrounds such as W+jets and tt̄ events, which we separate from the expected signals using three multivariate analysis techniques: boosted decision trees, Bayesian neural networks, and matrix-element calculations. A binned likelihood fit of the signal cross section plus background to the data from the combination of the results from the three analysis methods gives a cross section for single top-quark production of σ(pp̄→tb+X,tqb+X)=4.7±1.3pb. The probability to measure a cross section at this value or higher in the absence of signal is 0.014%, corresponding to a 3.6 standard deviation significance. The measured cross section value is compatible at the 10% level with the standard model prediction for electroweak top-quark production. We use the cross section measurement to directly determine the Cabibbo-Kobayashi-Maskawa quark mixing matrix element that describes the Wtb coupling and find |Vtbf1L|=1.31-0.21+0.25, where f1L is a generic vector coupling. This model-independent measurement translates into 0.68<|Vtb|≤1 at the 95% C.L. in the standard model. © 2008 The American Physical Society.Observation of the Bc meson in the exclusive decay Bc-->J/psipi.
Phys Rev Lett 101:1 (2008) 012001