Change search
Refine search result
16171819202122 901 - 950 of 121339
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 901. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Measurement of the Electron Charge Asymmetry in p(p)over-bar -> W plus X -> e nu plus X Events at root s=1.96 TeV2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 21, p. 211801-Article in journal (Refereed)
    Abstract [en]

    We present a measurement of the electron charge asymmetry in p (p) over bar -> W + X -> e nu + X events at a center of mass energy of 1.96 TeV using 0.75 fb(-1) of data collected with the D0 detector at the Fermilab Tevatron Collider. The asymmetry is measured as a function of the electron transverse momentum and pseudorapidity in the interval (-3.2, 3.2) and is compared with expectations from next-to-leading order calculations in perturbative quantum chromodynamics. These measurements will allow more accurate determinations of the proton parton distribution functions.

  • 902. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Measurement of the inclusive jet cross section in p(p)over-bar collisions at root s=1.96 TeV2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 6, p. 062001-Article in journal (Refereed)
    Abstract [en]

    We report on a measurement of the inclusive jet cross section in p (p) over bar collisions at a center-of-mass energy root s = 1.96 TeV using data collected by the D0 experiment at the Fermilab Tevatron Collider corresponding to an integrated luminosity of 0: 70 fb(-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.

  • 903. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Measurement of the Polarization of the Upsilon(1S) and Upsilon(2S) States in pp Collisions at s=1.96 TeV2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 18, p. 182004-Article in journal (Refereed)
    Abstract [en]

    We present a study of the polarization of the Upsilon(1S) and Upsilon(2S) states using a 1.3 fb(-1) data sample collected by the D0 experiment in 2002-2006 during run II of the Fermilab Tevatron Collider. We measure the polarization parameter alpha=(sigma(T)-2 sigma(L))/(sigma(T)+2 sigma(L)), where sigma(T) and sigma(L) are the transversely and longitudinally polarized components of the production cross section, as a function of the transverse momentum (p(T)(Upsilon)) for the Upsilon(1S) and Upsilon(2S). Significant p(T)(Upsilon)-dependent longitudinal polarization is observed for the Upsilon(1S). A comparison with theoretical models is presented.

  • 904. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Measurement of the ratio of the p(p)over-bar -> W + c-jet cross section to the inclusive p(p)over-bar -> W + jets cross section2008In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 666, no 1, p. 23-30Article in journal (Refereed)
    Abstract [en]

    We present a measurement of the fraction of inclusive W +jets events produced with net charm quantum number 11, denoted W + c-jet, in p collisions at root s = 1.96 TeV using approximately 1 fb(-1) of data collected by the DO detector at the Fermilab Tevatron Collider. We identify the W +jets events via the leptonic W boson decays. Candidate W + c-jet events are selected by requiring a jet containing a muon in association with a reconstructed W boson and exploiting the charge correlation between this muon and W boson decay lepton to perform a nearly model-independent background subtraction. We measure the fraction of W + c-jet events in the inclusive W +jets sample for jet PT > 20 GeV and pseudorapidity |eta| < 2.5 to be 0.074 +/- 0.019(stat.) +/-(0.012)(0.014) (syst.), in agreement with theoretical predictions. The probability that background fluctuations could produce the observed fraction of W + c-jet events is estimated to be 2.5 x 10(-4), which corresponds to a 3.5 sigma statistical significance.

  • 905. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Observation of the B(c) meson in the exclusive decay B(c)-> J/psi pi2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 1, p. 012001-Article in journal (Refereed)
    Abstract [en]

    A fully reconstructed B(c)-> J/psi pi signal is observed with the D0 detector at the Fermilab Tevatron p (p) over bar collider using 1.3 fb(-1) of integrated luminosity. The signal consists of 54 +/- 12 candidates with a significance that exceeds 5 standard deviations, and confirms earlier observations of this decay. The measured mass of the B(c) meson is 6300 +/- 14(stat)+/- 5(syst) MeV/c(2).

  • 906. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Observation of the Doubly Strange b Baryon Omega(-)(b)2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 23, p. 232002-Article in journal (Refereed)
    Abstract [en]

    We report the observation of the doubly strange b baryon Omega(-)(b) in the decay channel Omega(-)(b) -> J/psi Omega(-), with J/psi -> mu(+)mu(-) and Omega(-) -> Lambda K(-) -> (p pi(-))K(-), in p (p) over bar collisions at root s = 1.96 TeV. Using approximately 1.3 fb(-1) of data collected with the D0 detector at the Fermilab Tevatron Collider, we observe 17.8 +/- 4.9(stat) +/- 0.8(syst) Omega(-)(b) signal events at a mass of 6.165 +/- 0.010(stat) +/- 0.013(syst) GeV. The significance of the observed signal is 5.4 sigma, corresponding to a probability of 6.7 x 10(-8) of it arising from a background fluctuation.

  • 907. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Observation of ZZ Production in p(p)over-bar Collisions at root s=1.96 TeV2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 17, p. 171803-Article in journal (Refereed)
    Abstract [en]

    We present an observation for ZZ -> l(+) l(-) l'(+) l'(-) (l, l' =e or mu) production in p (p) over bar collisions at a center-of-mass energy of root s = 1.96 TeV. Using 1.7 fb(-1) of data collected by the D0 experiment at the Fermilab Tevatron Collider, we observe three candidate events with an expected background of 0.14(-0.02)(+0.03) events. The significance of this observation is 5.3 standard deviations. The combination of D0 results in this channel, as well as in ZZ -> l(+) l(-) v (v) over bar yields a significance of 5.7 standard deviations and a combined cross section of sigma(ZZ) = 1.60 +/- 0.63(stat)(-0.17)(+0.16)(syst) pb.

  • 908. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Precise Measurement of the Top-Quark Mass from lepton plus jets Events2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 18, p. 182001-Article in journal (Refereed)
    Abstract [en]

    We measure the mass of the top quark using top-quark pair candidate events in the lepton+jets channel from data corresponding to 1 fb(-1) of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron collider. We use a likelihood technique that reduces the jet energy scale uncertainty by combining an in situ jet energy calibration with the independent constraint on the jet energy scale (JES) from the calibration derived using photon+jets and dijet samples. We find the mass of the top quark to be 171.5 +/- 1.8(stat.+JES)+/- 1.1(syst.) GeV.

  • 909. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Relative rates of B meson decays into psi(2S) and J/psi mesons2009In: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 79, no 11, p. 111102-Article in journal (Refereed)
    Abstract [en]

    We report on a study of the relative rates of B meson decays into psi(2S) and J/psi mesons using 1.3 fb(-1) of p (p) over bar collisions at root s = 1.96 TeV recorded by the D0 detector operating at the Fermilab Tevatron Collider. We observe the channels B(s)(0) -> psi(2S)phi, B(s)(0) -> J/psi phi, B(+/-) -> psi(2S)K(+/-), and B(+/-) -> J/psi K(+/-) and we measure the relative branching fractions for these channels to be B(B(s)(0) -> psi(2S)phi)/B(B(s)(0) -> J/psi phi)=0.53 +/- 0.10(stat)+/- 0.07(syst)+/- 0.06(B), B(B(+) -> psi(2S)K(+))/B(B(+) -> J/psi K(+))=0.63 +/- 0.05(stat)+/- 0.03(syst)+/- 0.07(B), where the final error corresponds to the uncertainty in the J/psi and psi(2S) branching ratio into two muons.

  • 910. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Search for Anomalous Wtb Couplings in Single Top Quark Production2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 22, p. 221801-Article in journal (Refereed)
    Abstract [en]

    In 0.9 fb(-1) of pp collisions, the D0 Collaboration presented evidence for single top quark production in events with an isolated lepton, missing transverse momentum, and two to four jets. We examine these data to study the Lorentz structure of the Wtb coupling. The standard model predicts a left-handed vector coupling at the Wtb vertex. The most general lowest dimension, CP-conserving Lagrangian admits right-handed vector and left- or right-handed tensor couplings as well. We find that the data prefer the left-handed vector coupling and set upper limits on the anomalous couplings. These are the first direct constraints on a general Wtb interaction and the first direct limits on left- and right-handed tensor couplings.

  • 911. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et. al.,
    Search for Charged Higgs Bosons Decaying into Top and Bottom Quarks in pp Collisions2009In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 102, no 19, p. 191802-Article in journal (Refereed)
    Abstract [en]

    We describe a search for production of a charged Higgs boson, qq>-> H(+), reconstructed in the tb 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)(+), tan beta) plane for type I 2HDM is presented.

  • 912. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Search for decay of a fermiophobic Higgs boson h(f) -> gamma gamma with the D0 detector at root s=1.96 TeV2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 5, p. 051801-Article in journal (Refereed)
    Abstract [en]

    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(hf) > 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) -> gamma gamma) vs m(hf) which was not accessible at the CERN Large Electron-Positron Collider.

  • 913. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Search for Higgs bosons decaying to tau pairs in p(p)over-bar collisions with the D0 detector2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 7, p. 071804-Article in journal (Refereed)
    Abstract [en]

    We present a search for the production of neutral Higgs bosons phi decaying into tau(+)tau(-) final states in p (p) over bar collisions at a center-of-mass energy of 1.96 TeV. The data, corresponding to an integrated luminosity of approximately 1 fb(-1), were collected by the D0 experiment at the Fermilab Tevatron Collider. Limits on the production cross section times branching ratio are set. The results are interpreted in the minimal supersymmetric standard model yielding limits that are the most stringent to date at hadron colliders.

  • 914. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Search for large extra dimensions via single photon plus missing energy final states at root s=1.96 TeV2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 1, p. 011601-Article in journal (Refereed)
    Abstract [en]

    We report on a search for large extra dimensions in a data sample of approximately 1 fb(-1) of p (p) over bar collisions at root s=1.96 TeV. We investigate Kaluza-Klein graviton production with a photon and missing transverse energy in the final state. At the 95% C.L. we set limits on the fundamental mass scale M(D) from 884 to 778 GeV for two to eight extra dimensions.

  • 915. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Search for long-lived particles decaying into electron or photon pairs with the D0 detector2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 11, p. 111802-Article in journal (Refereed)
    Abstract [en]

    In this Letter we report on a search for long-lived particles that decay into final states with two electrons or photons. Such long-lived particles arise in a variety of theoretical models, such as hidden valleys and supersymmetry with gauge-mediated breaking. By precisely reconstructing the direction of the electromagnetic shower we are able to probe much longer lifetimes than previously explored. We see no evidence of the existence of such long-lived particles and interpret this search as a quasi model-independent limit on their production cross section, as well as a limit on a long-lived fourth generation quark.

  • 916. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Search for Neutral Higgs Bosons in Multi-b-Jet Events in pp Collisions at s=1.96 TeV2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 22, p. 221802-Article in journal (Refereed)
    Abstract [en]

    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. This production mode can be enhanced in the minimal supersymmetric standard model (MSSM). The search is performed in the three b quark channel using multijet triggered events corresponding to an integrated luminosity of 1 fb(-1). No statistically significant excess of events with respect to the predicted background is observed and limits are set in the MSSM parameter space.

  • 917. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Search for pair production of doubly charged Higgs bosons in the H(++)H(--)->mu(+)mu(+)mu(-)mu(-) final state2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 7, p. 071803-Article in journal (Refereed)
    Abstract [en]

    We report the results of a search for pair production of doubly charged Higgs bosons via p (p) over bar -> H(++)H(--)X ->mu(+)mu(+)mu(-)mu(-)X at root s=1.96 TeV. We use a data set corresponding to an integrated luminosity of 1.1 fb(-1) collected from 2002 to 2006 by the D0 detector at the Fermilab Tevatron Collider. In the absence of an excess above the standard model background, lower mass limits of M(H(L)(+/-+/-))> 150 GeV/c(2) and M(H(R)(+/-+/-))> 127 GeV/c(2) at 95% C.L. are set, respectively, for left-handed and right-handed doubly charged Higgs bosons assuming a 100% branching ratio into muons.

  • 918. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Search for scalar leptoquarks and T-odd quarks in the acoplanar jet topology using 2.5 fb(-1) of p(p)over-bar collision data at root s=1.96 TeV2008In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 668, no 5, p. 357-363Article in journal (Refereed)
    Abstract [en]

    A search for new physics in the acoplanar jet topology has been performed in 2.5 fb(-1) of data from p (p) over bar collisions at root s = 1.96 TeV, recorded by the DO detector at the Fermilab Tevatron Collider. The numbers of events with exactly two acoplanar jets and missing transverse energy are in good agreement with the Standard Model expectations. The result of this search has been used to set a lower mass limit of 205 GeV at the 95% C.L. on the mass of a scalar leptoquark when this particle decays exclusively into a quark and a neutrino. In the framework of the Little Higgs model with T-parity, limits have also been obtained on the T-odd quark mass as a function of the T-odd photon mass.

  • 919. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Search for scalar top quarks in the acoplanar charm jets and missing transverse energy final state in p(p)over-bar collisions at root s=1.96 TeV2008In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 665, no 1, p. 1-8Article in journal (Refereed)
    Abstract [en]

    We present a search for the pair production of scalar top quarks, (t) over tilde, using 995 pb(-1) of data collected in p (p) over bar collisions with the Dempty set detector at the Fermilab Tevatron Collider at root s = 1.96 TeV. Both scalar top quarks are assumed to decay into a charm quark and a neutralino ((chi) over tilde (0)(1)), where (chi) over tilde (0)(1) is the lightest supersymmetric particle. This leads to a final state with two acoplanar charm jets and missing transverse energy. We find the yield of such events to be consistent with the standard model expectation, and exclude sets of (t) over tilde and (chi) over tilde (0)(1) masses at the 95% C.L. that substantially extend the domain excluded by previous searches.

  • 920. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Search for the Standard Model Higgs Boson in the Missing Energy and Acoplanar b-Jet Topology at root s=1.96 TeV2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 25, p. 251802-Article in journal (Refereed)
    Abstract [en]

    We report a search for the standard model Higgs boson in the missing energy and acoplanar b-jet topology, using an integrated luminosity of 0.93 fb(-1) recorded by the D0 detector at the Fermilab Tevatron p (p) over bar Collider. The analysis includes signal contributions from p (p) over bar -> ZH -> v (v) over barb (b) over bar, as well as from WH production in which the charged lepton from the W boson decay is undetected. Neural networks are used to separate signal from background. In the absence of a signal, we set limits on sigma(p (p) over bar -> VH) x B(H -> b (b) over bar) at the 95% C.L. of 2.6-2.3 pb, for Higgs boson masses in the range 105-135 GeV, where V W, Z. The corresponding expected limits range from 2.8 to 2.0 pb.

  • 921. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Search for Third Generation Scalar Leptoquarks Decaying into tau b2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 24, p. 241802-Article in journal (Refereed)
    Abstract [en]

    We have searched for third generation leptoquarks (LQ(3)) using 1.05 fb(-1) of data collected with the D0 detector at the Fermilab Tevatron Collider operating at s=1.96 TeV. We set a 95% C.L. lower limit of 210 GeV on the mass of a scalar LQ(3) state decaying solely to a b quark and a tau lepton.

  • 922. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    Search for t(t)over-bar resonances in the lepton plus jets final state in p(p)over-bar collisions at root s=1.96 TeV2008In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 668, no 2, p. 98-104Article in journal (Refereed)
    Abstract [en]

    We present a search for a narrow-width heavy resonance decaying into top quark pairs (X -> t (t) over bar) in p (p) over bar collisions at root s = 1.96 TeV using approximately 0.9 fb(-1) of data collected with the DO detector at the Fermilab Tevatron Collider. This analysis considers t (t) over bar candidate events in the lepton plus jets channel with at least one identified b jet and uses the t (t) over bar invariant mass distribution to search for evidence of resonant production. We find no evidence for a narrow resonance X decaying to t (t) over bar. Therefore, we set upper limits on sigma x center dot B(X -> t (t) over bar) for different hypothesized resonance masses using a Bayesian approach. For a Topcolor-assisted technicolor model, the existence of a leptophobic Z' boson with mass M(Z') < 700 GeV and width Gamma(Z') = 0.012M(Z') can be excluded at the 95% C.L.

  • 923. Abazov, V. M.
    et al.
    Gollub, Nils
    Strandberg, Jonas
    University of Chicago.
    Zverev, E.G.
    et al.,
    ZZ -> l(+)l(-)nu(nu)overbar production in p(p)overbar collisions at root s=1.96 TeV2008In: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 78, no 7, p. 072002-Article in journal (Refereed)
    Abstract [en]

    We describe a search for Z boson pair production in p(p)overbar collisions at root s=1.96 TeV with the D0 detector at the Fermilab Tevatron Collider using a data sample corresponding to an integrated luminosity of 2.7 fb(-1). Using the final state decay ZZ ->center dot(+)center dot(-)nu(nu)overbar (where center dot=e or mu) we find a signal with a 2.6 standard deviations significance (2.0 expected) corresponding to a cross section of sigma(p(p)overbar -> ZZ+X)=2.01 +/- 0.93(stat)+/- 0.29(sys) pb.

  • 924. Abazov, V. M.
    et al.
    Strandberg, Jonas
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    et, al.
    Combined measurements of anomalous charged trilinear gauge-boson couplings from diboson production in p-pbar collisions at sqrt(s)=1.96 TeV2009In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445Article in journal (Refereed)
    Abstract [en]

    We present measurements of the anomalous WWgamma and WWZ trilinear gauge couplings from a combination of four diboson production and decay channels using data collected by the D0 detector at the Fermilab Tevatron Collider. These results represent the first high statistics combination of limits across different diboson production processes at the Tevatron and use data corresponding to an integrated luminosity of approximately 1 fb^-1. When respecting SU(2)_L x U(1)_Y symmetry, we measure central values and 68% C.L. allowed intervals of kappa_gamma=1.07^+0.16_-0.20, lambda =0.00^+0.05_-0.04 and g_1^Z=1.05 +/- 0.06. We present the most stringent measurements to date for the W boson magnetic dipole and electromagnetic quadrupole moments of mu_W=2.02^+0.08_-0.09 (e/2M_W) and q_W=-1.00 +/- 0.09 (e/M^2_W), respectively.

  • 925. Abazov, V. M.
    et al.
    Strandberg, Jonas
    KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
    et, al.
    Search for supersymmetry with gauge-mediated breaking in diphoton events at DØ2005In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 94, no 4Article in journal (Refereed)
    Abstract [en]

    We report the results of a search for supersymmetry (SUSY) with gauge-mediatedbreaking in the missing transverse energy distribution of inclusive diphoton events using 263 pb -1 of data collected by the DO experiment at the Fermilab Tevatron Collider in 2002-2004. No excess is observed above the background expected from standard model processes, and lower limits on the masses of the lightest neutralino and chargino of about 108 and 195 GeV, respectively, are set at the 95% confidence level. These are the most stringent limits to date for models with gauge-mediated SUSY breaking with a short-lived neutralino as the next-to-lightest SUSY particle. 

  • 926. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zivkovic, L.
    et al.,
    b-Jet identification in the D0 experiment2010In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 620, no 2-3, p. 490-517Article in journal (Refereed)
    Abstract [en]

    Algorithms distinguishing jets originating from b quarks from other jet flavors are important tools in the physics program of the D0 experiment at the Fermilab Tevatron p (p) over bar collider. This article describes the methods that have been used to identify b-quark jets, exploiting in particular the long lifetimes of b-flavored hadrons, and the calibration of the performance of these algorithms based on collider data.

  • 927. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    A novel method for modeling the recoil in W boson events at hadron colliders2009In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 609, no 2-3, p. 250-262Article in journal (Refereed)
    Abstract [en]

    We present a new method for modeling the hadronic recoil in W -> lv events produced at hadron colliders. The recoil is chosen from a library of recoils in Z -> ll data events and overlaid on a simulated W -> lv event. Implementation of this method requires that the data recoil library describe the proper-ties of the measured recoil as a function of the true, rather than the measured, transverse momentum of the boson. We address this issue using a multidimensional Bayesian unfolding technique. We estimate the statistical and systematic uncertainties from this method for the W boson mass and width measurements assuming 1 fb(-1) of data from the Fermilab Tevatron. The uncertainties are found to be small and comparable to those of a more traditional parameterized recoil model. For the highprecision measurements that will be possible with data from Run 11 of the Fermilab Tevatron and from the CERN LHC, the method presented in this paper may be advantageous, since it does not require an understanding of the measured recoil from first principles.

  • 928. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Combination of t(t)over-bar cross section measurements and constraints on the mass of the top quark and its decays into charged Higgs bosons2009In: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 80, no 7, p. 071102-Article in journal (Refereed)
    Abstract [en]

    We combine measurements of the top quark pair production cross section in p (p) over bar collisions in the l + jets, ll, and tau l final states ( where l is an electron or muon) at a center of mass energy of root s = 1.96 TeV in 1 fb(-1) of data collected with the D0 detector. For a top quark mass of 170 GeV/c(2), we obtain sigma(t (t) over bar) = 8.18(-0.87)(+0.98) pb in agreement with the theoretical prediction. Based on predictions from higher order quantum chromodynamics, we extract a mass for the top quark from the combined t (t) over bar cross section, consistent with the world average of the top quark mass. In addition, the ratios of t (t) over bar cross sections in different final states are used to set upper limits on the branching fractions B(t -> H(+)b -> tau(+) vb) and B(t -> H(+)b -> c (s) over barb) as a function of the charged Higgs boson mass.

  • 929. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Dependence of the t(t)over-bar production cross section on the transverse momentum of the top quark2010In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 693, no 5, p. 515-521Article in journal (Refereed)
    Abstract [en]

    We present a measurement of the differential cross section for t (t) over bar events produced in p (p) over bar collisions at root s = 1.96 TeV as a function of the transverse momentum (p(T)) of the top quark. The selected events contain a high-p(T) lepton (l), a large imbalance in p(T). four or more jets with at least one candidate for a b jet, and correspond to 1 fb(-1) of integrated luminosity recorded with the D0 detector. Objects in the event are associated through a constrained kinematic fit to the t (t) over bar -> WbW (b) over bar -> lvbq (q) over bar' (b) over bar process. Results from next and next-to-next-to-leading-order perturbative QCD calculations agree with the measured differential cross section. Comparisons are also provided to predictions from Monte Carlo event generators using QCD calculations at different levels of precision.

  • 930. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Determination of the strong coupling constant from the inclusive jet cross section in pp collisions at s=1.96 TeV2009In: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 80, no 11, p. 111107-Article in journal (Refereed)
    Abstract [en]

    We determine the strong coupling constant alpha(s) and its energy dependence from the p(T) dependence of the inclusive jet cross section in pp collisions at s=1.96 TeV. The strong coupling constant is determined over the transverse momentum range 50 < p(T)< 145 GeV. Using perturbative QCD calculations to order O(alpha(3)(s)) combined with O(alpha(4)(s)) contributions from threshold corrections, we obtain alpha(s)(M(Z))=0.1161(-0.0048)(+0.0041). This is the most precise result obtained at a hadron-hadron collider.

  • 931. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Direct Measurement of the Mass Difference between Top and Antitop Quarks2009In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 103, no 13, p. 132001-Article in journal (Refereed)
    Abstract [en]

    We present a measurement of the mass difference between t and (t) over bar quarks in lepton + jets final states of t (t) over bar events in 1 fb(-1) of data collected with the D0 detector from Fermilab Tevatron Collider p (p) over bar collisions at root s = 1.96 TeV. The measured mass difference of 3.8 +/- 3.7 GeV is consistent with the equality of t and (t) over bar masses. This is the first direct measurement of a mass difference between a quark and its antiquark partner.

  • 932. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Direct Measurement of the W Boson Width2009In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 103, no 23, p. 231802-Article in journal (Refereed)
    Abstract [en]

    We present a direct measurement of the width of the W boson using the shape of the transverse mass distribution of W -> e nu candidate events. Data from approximately 1 fb(-1) of integrated luminosity recorded at s=1.96 TeV by the D0 detector at the Fermilab Tevatron pp collider are analyzed. We use the same methods and data sample that were used for our recently published W boson mass measurement, except for the modeling of the recoil, which is done with a new method based on a recoil library. Our result, 2.028 +/- 0.072 GeV, is in agreement with the predictions of the standard model.

  • 933. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Double parton interactions in gamma+3 jet events in p(p)over-bar collisions at root s=1.96 TeV2010In: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 81, no 5, p. 052012-Article in journal (Refereed)
    Abstract [en]

    We have used a sample of gamma + 3 jets events collected by the D0 experiment with an integrated luminosity of about 1 fb(-1) to determine the fraction of events with double parton scattering (f(DP)) in a single p (p) over bar collision at root s = 1.96 TeV. The DP fraction and effective cross section (sigma(eff)), a process-independent scale parameter related to the parton density inside the nucleon, are measured in three intervals of the second (ordered in p(T)) jet transverse momentum p(T)(jet2) within the range 15 <= p(T)(jet2) <= 30 GeV. In this range, f(DP) varies between 0.23 <= f(DP) <= 0.47, while sigma(eff) has the average value sigma(ave)(eff) = 16.4 +/- 0.3(stat) +/- 2.3(syst) mb.

  • 934. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor, MI .
    Zverev, E. G.
    et al.,
    Measurement of Dijet Angular Distributions at s=1.96 TeV and Searches for Quark Compositeness and Extra Spatial Dimensions2009In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 103, no 19, p. 191803-Article in journal (Refereed)
    Abstract [en]

    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.

  • 935. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Measurement of the t-channel single top quark production cross section2010In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 682, no 4-5, p. 363-369Article in journal (Refereed)
    Abstract [en]

    The DO 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 p (p) over bar 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.

  • 936. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Measurement of the top quark mass in final states with two leptons2009In: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 80, no 9, p. 092006-Article in journal (Refereed)
    Abstract [en]

    We present measurements of the top quark mass (m(t)) in tt candidate events with two final state leptons using 1 fb(-1) of data collected by the D0 experiment. Our data sample is selected by requiring two fully identified leptons or by relaxing one lepton requirement to an isolated track if at least one jet is tagged as a b jet. The top quark mass is extracted after reconstructing the event kinematics under the tt hypothesis using two methods. In the first method, we integrate over expected neutrino rapidity distributions, and in the second we calculate a weight for the possible top quark masses based on the observed particle momenta and the known parton distribution functions. We analyze 83 candidate events in the data and obtain m(t)=176.2 +/- 4.8(stat)+/- 2.1(sys) GeV and m(t)=173.2 +/- 4.9(stat)+/- 2.0(sys) GeV for the two methods, respectively. Accounting for correlations between the two methods, we combine the measurements to obtain m(t)=174.7 +/- 4.4(stat)+/- 2.0(sys) GeV.

  • 937. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Measurement of the t(t)over-bar cross section using high-multiplicity jet events2010In: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 82, no 3, p. 032002-Article in journal (Refereed)
    Abstract [en]

    We present a measurement of the t (t) over bar cross section using high-multiplicity jet events produced in p (p) over bar collisions at root 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/c(2), is 6.9 +/- 2.0 pb, in agreement with theoretical expectations.

  • 938. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Measurement of the t(t)over-bar production cross section and top quark mass extraction using dilepton events in p(p)over-bar collisions2009In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 679, no 3, p. 177-185Article in journal (Refereed)
    Abstract [en]

    We present a measurement of the top quark pair production cross section in p (p) over bar collisions at root s = 1.96 TeV using approximately 1 fb(-1) collected with the DO detector. We consider decay channels containing two high p(T) charged leptons where one lepton is identified as an electron or a muon while the other lepton can be an electron, a muon or a hadronically decaying tau lepton. For a mass of the top quark of 170 GeV, the measured cross section is 7.5(-1.0)(+1.0)(stat)(-0.6)(+0.7)(syst)(-0.5)(+0.6)(lumi) pb. Using l tau events only, we measure: sigma(t (t) over bar) x B(t (t) over bar -> l tau b (b) over bar) = 0.13(-0.08)(+0.09)(stat)(-0.06)(+0.06)(syst)(-0.02)(+0.02)(lumi) pb. Comparing the measured cross section as a function of the mass of the top quark with a partial next-to-next-to leading order Quantum Chroniodynamics theoretical prediction, we extract a mass of the top quark of 171.5(-8.8)(+9-9) GeV, in agreement with direct measurements.

  • 939. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Measurement of the W Boson Mass2009In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 103, no 14, p. 141801-Article in journal (Refereed)
    Abstract [en]

    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.

  • 940. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Measurement of the WW Production Cross Section with Dilepton Final States in pp Collisions at s=1.96 TeV and Limits on Anomalous Trilinear Gauge Couplings2009In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 103, no 19, p. 191801-Article in journal (Refereed)
    Abstract [en]

    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.

  • 941. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Measurement of trilinear gauge boson couplings from WW plus WZ -> lvjj events in p(p)over-bar collisions at root s=1.96 TeV2009In: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 80, no 5, p. 053012-Article in journal (Refereed)
    Abstract [en]

    We present a direct measurement of trilinear gauge boson couplings at gamma WW and ZWW vertices inWW and WZ events produced in p (p) over bar collisions at root s = 1:96 TeV. We consider events with one electron or muon, missing transverse energy, and at least two jets. The data were collected using the D0 detector and correspond to 1:1 fb(-1) of integrated luminosity. Considering two different relations between the couplings at the gamma WW and ZWW vertices, we measure these couplings at 68% C.L. to be kappa(gamma) = 1.07(-0.29)(+0.26) lambda = 0.00(-0.06)(+0.00), and g(1)(Z) = 1.04(-0.09)(+0.09) in a scenario respecting SU(2)(L) circle times U(1)(Y) gauge symmetry and kappa = 1.04(-0.11)(+0.11) and lambda = 0.00(-0.06)(+0.06) in an "equal couplings'' scenario.

  • 942. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Measurement of Z/gamma* plus jet plus X angular distributions in p(p)over-bar collisions at root s=1.96 TeV2010In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 682, no 4-5, p. 370-380Article in journal (Refereed)
    Abstract [en]

    We present the first measurements at a hadron collider of differential cross sections for Z/gamma* + jet + X production in Delta phi(Z. jet), vertical bar Delta y(Z, jet)vertical bar and vertical bar y(boost)(Z + jet)vertical bar. Vector boson production in association with jets is an excellent probe of QCD and constitutes the main background to many small cross section processes, such as associated Higgs production. These measurements are crucial tests of the predictions of perturbative QCD and current event generators, which have varied success in describing the data. Using these measurements as inputs in tuning event generators will increase the experimental sensitivity to rare signals.

  • 943. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Measurements of differential cross sections of Z/gamma* plus jets plus X events in p(p)over-bar collisions at root s=1.96 TeV2009In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 678, no 1, p. 45-54Article in journal (Refereed)
    Abstract [en]

    We present cross section measurements for Z/gamma* + jets + X production, differential in the transverse momenta of the three leading jets. The data sample was collected with the DO detector at the Fermilab Tevatron p (p) over bar collider at a center-of-mass energy of 1.96 TeV and corresponds to an integrated luminosity of 1 fb(-1). Leading and next-to-leading order perturbative QCD predictions are compared with the measurements. and agreement is found within the theoretical and experimental uncertainties. We also make comparisons with the predictions of four event generators. Two parton-shower-based generators show significant shape and normalization differences with respect to the data. In contrast, two generators combining tree-level matrix elements with a parton shower give a reasonable description of the shapes observed in data. but the predicted normalizations show significant differences with respect to the data, reflecting large scale Uncertainties. For specific choices of scales, the normalizations for either generator can be made to agree with the measurements.

  • 944. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Observation of Single Top-Quark Production2009In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 103, no 9, p. 092001-Article in journal (Refereed)
    Abstract [en]

    We report observation of the electroweak production of single top quarks in pp collisions at s=1.96 TeV based on 2.3 fb(-1) of data collected by the D0 detector at the Fermilab Tevatron Collider. Using events containing an isolated electron or muon and missing transverse energy, together with jets originating from the fragmentation of b quarks, we measure a cross section of sigma(pp -> tb+X,tqb+X)=3.94 +/- 0.88 pb. The probability to measure a cross section at this value or higher in the absence of signal is 2.5x10(-7), corresponding to a 5.0 standard deviation significance for the observation.

  • 945. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Search for a Resonance Decaying into WZ Boson Pairs in p(p)over-bar Collisions2010In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 104, no 6, p. 061801-Article in journal (Refereed)
    Abstract [en]

    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 p (p) over bar 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.

  • 946. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Search for associated production of charginos and neutralinos in the trilepton final state using 2.3 fb(-1) of data2009In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 680, no 1, p. 34-43Article in journal (Refereed)
    Abstract [en]

    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.

  • 947. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Search for charged Higgs bosons in decays of top quarks2009In: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 80, no 5, p. 051107-Article in journal (Refereed)
    Abstract [en]

    We present a search for charged Higgs bosons in decays of top quarks, in the mass range 80 < m(H+) < 155 GeV, assuming the subsequent decay H(+) -> tau(+)nu(tau) (and its charge conjugate). Using 0.9 fb(-1) of lepton + jets data collected with the D0 detector at the Fermilab Tevatron p (p) over bar collider, operating at a center of mass energy root s = 1.96 TeV, we find no evidence for a H(+/-) signal. Hence we exclude branching ratios B(t -> H(+)b) > 0.24 for m(H+) 80 GeV and B(t -> H(+)b) > 0.19 for m(H+) = 155 GeV at the 95% C.L.

  • 948. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Search for charged Higgs bosons in top quark decays2009In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 682, no 3, p. 278-286Article in journal (Refereed)
    Abstract [en]

    We present a search for charged Higgs bosons in top quark decays. We analyze the e + jets, mu + jets, ee, e mu, mu mu, tau e and tau mu final states from top quark pair production events, using data from about 1 fb (1) of integrated luminosity recorded by the DO 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 tau lepton and a tau neutrino and a third one where both decays appear. We extract limits on the branching ratio B(t -> H(+)b) for all these models. We use two methods, one where the t (t) over bar production cross section is fixed, and one where the cross section is fitted simultaneously with B(t -> H(+)b). Based on the extracted limits, we exclude regions in the charged Higgs boson mass and tan beta parameter space for different scenarios of the minimal supersymmetric standard model.

  • 949. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Univ Michigan, Ann Arbor.
    Zverev, E. G.
    et al.,
    Search for CP violation in B(s)(0) -> mu(+) D(s)(-) X decays in p(p)over-bar collisions at root s=1.96 TeV2010In: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 82, no 1, p. 012003-Article in journal (Refereed)
    Abstract [en]

    We have performed a search for CP violation in a sample of B(s)(0) -> mu(+)D(s)(-)X decays corresponding to 5 fb(-1) of proton-antiproton collisions collected by the D0 detector in Run II at the Fermilab Tevatron Collider. New physics in B(s)(0) mixing could contribute a significant CP violating weak phase, which would be observed as a difference in the decay-time distribution for B(s)(0) -> (B) over bar (0)(s) oscillated states versus that for (B) over bar (0)(s) -> B(s)(0). A fit to the decay-time distributions of the B(s)(0)/(B) over bar (0)(s) candidates yields the flavor-specific asymmetry as a(fs)(s) = [-1.7 +/- 9.1(stat)(-1.5)(+1.4)(syst) x 10(-3), which excludes CP violation due to new physics within the experimental sensitivity.

  • 950. Abazov, V. M.
    et al.
    Strandberg, Jonas
    Zverev, E. G.
    et al.,
    Search for Dark Photons from Supersymmetric Hidden Valleys2009In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 103, no 8, p. 081802-Article in journal (Refereed)
    Abstract [en]

    We search for a new light gauge boson, a dark photon, with the D0 experiment. In the model we consider, supersymmetric partners are pair produced and cascade to the lightest neutralinos that can decay into the hidden sector state plus either a photon or a dark photon. The dark photon decays through its mixing with a photon into fermion pairs. We therefore investigate a previously unexplored final state that contains a photon, two spatially close leptons, and large missing transverse energy. We do not observe any evidence for dark photons and set a limit on their production.

16171819202122 901 - 950 of 121339
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf