We measure the top quark mass (m(t)) in p ̄p collisions at a center of mass energy √s = 1.96 TeV using dilepton t ̄t→W(+)bW(-) ̄b→ℓ(+)ν(ℓ)bℓ(-) ̄ν(ℓ) ̄b events, where ℓ denotes an electron, a muon, ...or a tau that decays leptonically. The data correspond to an integrated luminosity of 5.4 fb(-1) collected with the D0 detector at the Fermilab Tevatron Collider. We obtain m(t)=174.0±1.8(stat)±2.4(syst) GeV, which is in agreement with the current world average m(t)=173.3±1.1 GeV. This is currently the most precise measurement of m(t) in the dilepton channel.
We report on a search for charged massive long-lived particles (CMLLPs), based on 5.2 fb(-1) of integrated luminosity collected with the D0 detector at the Fermilab Tevatron pp collider. We search ...for events in which one or more particles are reconstructed as muons but have speed and ionization energy loss (dE/dx) inconsistent with muons produced in beam collisions. CMLLPs are predicted in several theories of physics beyond the standard model. We exclude pair-produced long-lived gauginolike charginos below 267 GeV and Higgsino-like charginos below 217 GeV at 95% C.L., as well as long-lived scalar top quarks with mass below 285 GeV.
We study WW and WZ production with lvqq (l = e, mu) final states using data collected by the D0 detector at the Fermilab Tevatron Collider corresponding to 4.3 fb(-1) of integrated luminosity from p ...(p) over bar collisions at root s = 1.96 TeV. Assuming the ratio between the production cross sections sigma(WW) and sigma(WZ) as predicted by the standard model, we measure the total WV (V = W, Z) cross section to be sigma(WV) = 19.6(-3.0)(+3.2) pb and reject the background-only hypothesis at a level of 7.9 standard deviations. We also use b-jet discrimination to separate the WZ component from the dominant WW component. Simultaneously fitting WW and WZ contributions, we measure sigma(WW) = 15.9(-3.2)(+3.7) pb and sigma(WZ) = 3.3(-3.3)(+4.1) pb, which is consistent with the standard model predictions.
This paper reports on the charged pion production yields measured by the SPY/NA56 experiment for 450 GeV/c proton interactions on beryllium targets. The present data cover a secondary momentum range ...from 7 GeV/c to 135 GeV/c in the forward direction. An experimental accuracy ranging from 5 to 10%, depending on the beam momentum, has been achieved, limited mainly by the knowledge of the beam acceptance. These results will be relevant in the calculation of neutrino fluxes in present and future neutrino beams.
We present the first search for an electrically charged resonance W' decaying to a WZ boson pair using 4.1 fb(-1) of integrated luminosity collected with the D0 detector at the Fermilab Tevatron pp ...collider. The WZ pairs are reconstructed through their decays into three charged leptons (l=e, mu). A total of 9 data events is observed in good agreement with the background prediction. We set 95% C.L. limits on the W'WZ coupling and on the W' production cross section multiplied by the branching fractions. We also exclude W' masses between 188 and 520 GeV within a simple extension of the standard model and set the most restrictive limits to date on low-scale technicolor models.
We present a search for the standard model Higgs boson in final states with an electron or muon and a hadronically decaying tau lepton in association with zero, one, or two or more jets using data ...corresponding to an integrated luminosity of up to 7.3 fb(-1) collected with the D0 detector at the Fermilab Tevatron collider. The analysis is sensitive to Higgs boson production via gluon-gluon fusion, associated vector boson production, and vector boson fusion, and to Higgs boson decays to tau tau, WW, ZZ and b (b) over bar pairs. Observed (expected) limits are set on the ratio of 95% C.L. upper limits on the cross section times branching ratio, relative to those predicted by the Standard Model, of 22 (14) at a Higgs boson mass of 115 GeV and 6.8 (7.7) at 165 GeV.
We provide the most precise measurement of the WW production cross section in pp collisions to date at a center of mass energy of 1.96 TeV, and set limits on the associated trilinear gauge couplings. ...The WW -> l nu l(')nu (l, l(')=e, mu) decay channels are analyzed in 1 fb(-1) of data collected by the D0 detector at the Fermilab Tevatron Collider. The measured cross section is sigma(pp -> WW)=11.5 +/- 2.1(stat+syst)+/- 0.7(lumi) pb. One- and two-dimensional 95% C.L. limits on trilinear gauge couplings are provided.
We present a search for Kaluza-Klein (KK) particles predicted by models with universal extra dimensions (UED) using a data set corresponding to an integrated luminosity of 7.3 fb(-1), collected by ...the D0 detector at a pp center-of-mass energy of 1.96 TeV. The decay chain of KK particles can lead to a final state with two muons of the same charge. This signature is used to set a lower limit on the compactification scale of R(-1)>260 GeV in a minimal UED model.
A scintillating fiber tracker system consisting of more than one million fibers has been successfully constructed and made operational for the CERN WA95/CHORUS experiment. The design and construction ...of the tracker system as well as its opto-electronic readout are described. The performance of the detector with high-energy muons is presented.
We present a search for Kaluza-Klein (KK) particles predicted by models with universal extra dimensions (UED) using a data set corresponding to an integrated luminosity of 7.3 fb(-1), collected by ...the D0 detector at a p (p) over bar center-of-mass energy of 1.96 TeV. The decay chain of KK particles can lead to a final state with two muons of the same charge. This signature is used to set a lower limit on the compactification scale of R-1 > 260 GeV in a minimal UED model.
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