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Träfflista för sökning "WFRF:(Haley C. S.) ;pers:(Fox H.);pers:(Desai S.);pers:(Banerjee S.);srt2:(2011)"

Sökning: WFRF:(Haley C. S.) > Fox H. > Desai S. > Banerjee S. > (2011)

  • Resultat 1-10 av 40
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1.
  • Åsman, Barbro, et al. (författare)
  • Search for a heavy neutral gauge boson in the dielectron channel with 5.4 fb(-1) of p(p)over-bar collisions at root s=1.96 TeV
  • 2011
  • Ingår i: Physics Letters B. - 0370-2693. ; 695:1-4, s. 88-94
  • Tidskriftsartikel (refereegranskat)abstract
    • We report the results of a search for a heavy neutral gauge boson Z' decaying into the dielectron final state using data corresponding to an integrated luminosity of 5.4 fb(-1) collected by the D0 experiment at the Fermilab Tevatron Collider. No significant excess above the standard model prediction is observed in the dielectron invariant-mass spectrum. We set 95 sigma(p (p) over bar -> Z') x BR(Z' -> ee) depending on the dielectron invariant mass. These cross section limits are used to determine lower mass limits for bosons in a variety of models. For the sequential standard model boson a lower mass limit of 1023 GeV is obtained.
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2.
  • Abazov, V. M., et al. (författare)
  • Determination of the Width of the Top Quark
  • 2011
  • Ingår i: Physical Review Letters. - 0031-9007. ; 106:2, s. 022001
  • Tidskriftsartikel (refereegranskat)abstract
    • We extract the total width of the top quark, Gamma(t), from the partial decay width Gamma(t -> Wb) measured using the t-channel cross section for single top-quark production and from the branching fraction B(t -> Wb) measured in t (t) over bar t events using up to 2.3 fb(-1) of integrated luminosity collected by the D0 Collaboration at the Tevatron p (p) over bar Collider. The result is Gamma(t) = 1.99(-0.55)(+0.69) GeV, which translates to a top-quark lifetime of tau(t) = (3.3-(+1.3)(0.9)) x 10(-25) s. Assuming a high mass fourth generation b' quark and unitarity of the four-generation quark-mixing matrix, we set the first upper limit on vertical bar V-tb'vertical bar < 0.63 at 95% C.L.
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3.
  • Abazov, V. M., et al. (författare)
  • High mass exclusive diffractive dijet production in p(p)over-bar collisions at root s=1.96 TeV
  • 2011
  • Ingår i: Physics Letters B. - 0370-2693. ; 705:3, s. 193-199
  • Tidskriftsartikel (refereegranskat)abstract
    • We present evidence for diffractive exclusive dijet production with an invariant dijet mass greater than 100 GeV in data collected with the DO experiment at the Fermilab Tevatron Collider. A discriminant based on calorimeter information is used to measure a significant number of events with little energy (typically less than 10 GeV) outside the dijet system, consistent with the diffractive exclusive dijet production topology. The probability for these events to be explained by other dijet production processes is 2 x 10(-6), corresponding to a 4.7 standard deviation significance.
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4.
  • Abazov, V. M., et al. (författare)
  • Precise Study of the Z/gamma* Boson Transverse Momentum Distribution in p(p)over-bar Collisions Using a Novel Technique
  • 2011
  • Ingår i: Physical Review Letters. - 0031-9007. ; 106:12, s. 122001
  • Tidskriftsartikel (refereegranskat)abstract
    • Using 7.3 fb(-1) of p (p) over bar collisions collected by the D0 detector at the Fermilab Tevatron, we measure the distribution of the variable phi(eta)*, which probes the same physical effects as the Z/gamma* boson transverse momentum, but is less susceptible to the effects of experimental resolution and efficiency. A QCD prediction is found to describe the general features of the phi(eta)* distribution, but is unable to describe its detailed shape or dependence on boson rapidity. A prediction that includes a broadening of transverse momentum for small values of the parton momentum fraction is strongly disfavored.
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5.
  • Abazov, V. M., et al. (författare)
  • Search for pair production of the scalar top quark in the electron plus muon final state
  • 2011
  • Ingår i: Physics Letters B. - 0370-2693. ; 696:4, s. 321-327
  • Tidskriftsartikel (refereegranskat)abstract
    • We report the result of a search for the pair production of the lightest supersymmetric partner of the top quark ((t) over tilde (1)) in p (p) over bar collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider corresponding to an integrated luminosity of 5.4 fb(-1). The scalar top quarks are assumed to decay into a b quark, a charged lepton, and a scalar neutrino ((nu) over bar). and the search is performed in the electron plus muon final state. No significant excess of events above the standard model prediction is detected, and substantially improved exclusion limits at the 95% C.L. are set in the the (M-(t) over tilde1, M-(nu) over tilde mass plane.
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6.
  • Abazov, V. M., et al. (författare)
  • Measurement of the WZ -> lvll cross section and limits on anomalous triple gauge couplings in p(p)over-bar collisions at root s=1.96 TeV
  • 2011
  • Ingår i: Physics Letters B. - 0370-2693. ; 695:1-4, s. 67-73
  • Tidskriftsartikel (refereegranskat)abstract
    • We present a new measurement of the WZ -> lvll (l = e, mu) cross section and limits on anomalous triple gauge couplings. Using 4.1 fb(-1) of integrated luminosity of p (p) over bar collisions at root s = 1.96 TeV, we observe 34 WZ candidate events with an estimated background of 6.0 +/- 0.4 events. We measure the WZ production cross section to be 3.89(-0.90)(+1.07) pb, in good agreement with the standard model prediction. We find no evidence for anomalous WWZ couplings and set 95% C.L. limits on the coupling parameters, -0.077 < lambda(z) < 0.093 and -0.029 < Delta kappa(z) < 0.080 in the HISZ parameterization for a Lambda = 2 TeV form factor scale. These are the best limits to date obtained from the direct measurement of the WWZ vertex.
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7.
  • Åsman, Barbro, et al. (författare)
  • Model-independent measurement of t-channel single top quark production in p(p)over-bar collisions at,root s=1.96 TeV
  • 2011
  • Ingår i: Physics Letters B. - 0370-2693. ; 705:4, s. 313-319
  • Tidskriftsartikel (refereegranskat)abstract
    • We present a model-independent measurement of t-channel electroweak production of single top quarks in p collisions at root s = 1.96 TeV. Using 5.4 fb(-1) of integrated luminosity collected by the DO detector at the Fermilab Tevatron Collider, and selecting events containing an isolated electron or muon, missing transverse energy and one or two jets originating from the fragmentation of b quarks, we measure a cross section sigma (p (p) over bar -> tqb + X) = 2.90 +/- 0.59 (stat + syst) pb for a top quark mass of 172.5 GeV. The probability of the background to fluctuate and produce a signal as large as the one observed is 1.6 x 10(-8), corresponding to a significance of 5.5 standard deviations. (C) 2011 Elsevier B.V. All rights reserved.
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8.
  • Åsman, Barbro, et al. (författare)
  • Search for Resonant WW and WZ Production in p(p)over-bar Collisions at root s=1.96 TeV
  • 2011
  • Ingår i: Physical Review Letters. - 0031-9007. ; 107:1, s. 011801
  • Tidskriftsartikel (refereegranskat)abstract
    • We search for resonant WW or WZ production by using up to 5: 4 fb(-1) of integrated luminosity collected by the D0 experiment in run II of the Fermilab Tevatron Collider. The data are consistent with the standard model background expectation, and we set limits on a resonance mass by using the sequential standard model W' boson and the Randall-Sundrum model graviton G as benchmarks. We exclude a sequential standard model W' boson in the mass range 180-690 GeV and a Randall-Sundrum graviton in the range 300-754 GeV at 95% C. L.
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9.
  • Åsman, Barbro, et al. (författare)
  • Search for Single Vectorlike Quarks in p(p)over-bar Collisions at root s=1.96 TeV
  • 2011
  • Ingår i: Physical Review Letters. - 0031-9007. ; 106:8, s. 081801
  • Tidskriftsartikel (refereegranskat)abstract
    • We present a search for hypothetical vectorlike quarks in p (p) over bar collisions at root s = 1.96 TeV. The data were collected by the D0 detector at the Fermilab Tevatron Collider and correspond to an integrated luminosity of 5.4 fb(-1). We select events with a final state composed of a W or Z boson and a jet consistent with a heavy object decay. We observe no significant excess in comparison to the background prediction and set limits on production cross sections for vectorlike quarks decaying to W + jet and Z + jet. These are the most stringent limits to date for electroweak single vectorlike quark production at hadron colliders.
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10.
  • Abazov, V. M., et al. (författare)
  • Determination of the pole and (MS)over-bar masses of the top quark from the t(t)over-bar cross section
  • 2011
  • Ingår i: Physics Letters B. - 0370-2693. ; 703:4, s. 422-427
  • Tidskriftsartikel (refereegranskat)abstract
    • We use higher-order quantum chromodynamics calculations to extract the mass of the top quark from the t (t) over bar cross section measured in the lepton + jets channel in p (p) over bar collisions at root s = 1.96 TeV using 5.3 fb(-1) of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider. The extracted top quark pole mass and (MS) over bar mass are compared to the current Tevatron average top quark mass obtained from direct measurements.
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  • Resultat 1-10 av 40
  • [1]234Nästa
 
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