| 11. |
- Abazov, V. M., et al.
(author)
-
Measurement of the t(t)over-bar production cross section in p(p)over-bar collisions at root s=1.96 TeV
- 2008
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 100:19:100, s. 192004-
-
Journal article (peer-reviewed)abstract
- We measure the t (t) over bar production cross section in p (p) over bar collisions at root s = 1.96 TeV in the lepton + jets channel. Two complementary methods discriminate between signal and background: b tagging and a kinematic likelihood discriminant. Based on 0.9 fb(-1) of data collected by the D0 detector at the Fermilab Tevatron Collider, we measure sigma(t (t) over bar) = 7.62 +/- 0.85 pb, assuming the current world average m(t) = 172.6 GeV. We compare our cross section measurement with theory predictions to determine a value for the top-quark mass of 170 +/- 7 GeV.
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| 12. |
- Abazov, V. M., et al.
(author)
-
Model-independent measurement of the W-boson helicity in top-quark decays at D0
- 2008
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 100:6
-
Journal article (peer-reviewed)abstract
- We present the first model-independent measurement of the helicity of W bosons produced in top quark decays, based on a 1 fb(-1) sample of candidate t (t) over bar events in the dilepton and lepton plus jets channels collected by the D0 detector at the Fermilab Tevatron p (p) over bar Collider. We reconstruct the angle theta(*) between the momenta of the down-type fermion and the top quark in the W boson rest frame for each top quark decay. A fit of the resulting cos theta(*) distribution finds that the fraction of longitudinal W bosons f(0)=0.425 +/- 0.166(stat)+/- 0.102(syst) and the fraction of right-handed W bosons f(+)=0.119 +/- 0.090(stat)+/- 0.053(syst), which is consistent at the 30% C.L. with the standard model.
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| 13. |
- Abazov, V. M., et al.
(author)
-
Observation and properties of the orbitally excited B-s2* meson
- 2008
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 100:8, s. 082002-:100, s. 082002-
-
Journal article (peer-reviewed)abstract
- We report the direct observation of the excited L=1 state B-s2* in fully reconstructed decays to B+K-. The mass of the B-s2* meson is measured to be 5839.6 +/- 1.1(stat)+/- 0.7(syst) MeV/c(2), and its production rate relative to the B+ meson is measured to be [1.15 +/- 0.23(stat)+/- 0.13(syst)]%.
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| 14. |
- Abazov, V. M., et al.
(author)
-
Observation of the B-c meson in the exclusive decay B-c -> J/psi pi
- 2008
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 101:1, s. 012001-:101, s. 012001-
-
Journal article (peer-reviewed)abstract
- 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).
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| 15. |
- Abazov, V. M., et al.
(author)
-
Search for decay of a fermiophobic Higgs boson h(f) -> gamma gamma with the D0 detector at root s=1.96 TeV
- 2008
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 101:5, s. 051801-:101, s. 051801-
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Journal article (peer-reviewed)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(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.
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| 16. |
- Abazov, V. M., et al.
(author)
-
Search for excited electrons in p(p)over-bar collisions at root s=1.96 TeV
- 2008
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; D:77, s. 091102-
-
Journal article (peer-reviewed)abstract
- We present the results of a search for the production of an excited state of the electron, e(*), in proton-antiproton collisions at root s = 1.96 TeV. The data were collected with the D0 experiment at the Fermilab Tevatron Collider and correspond to an integrated luminosity of approximately 1 fb(-1). We search for e(*) in the process p (p) over bar -> e(*)e, with the e(*) subsequently decaying to an electron plus photon. No excess above the standard model background is observed. Interpreting our data in the context of a model that describes e(*) production by four-fermion contact interactions and e(*) decay via electroweak processes, we set 95% C.L. upper limits on the production cross section ranging from 8.9 to 27 fb, depending on the mass of the excited electron. Choosing the scale for contact interactions to be Lambda = 1 TeV, excited electron masses below 756 GeV are excluded at the 95% C.L.
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| 17. |
- Abazov, V. M., et al.
(author)
-
Search for flavor-changing-neutral-current D meson decays
- 2008
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 100:10, s. 101801-:100, s. 101801-
-
Journal article (peer-reviewed)abstract
- We study the flavor-changing-neutral-current process c -> u mu(+)mu(-) 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 see clear indications of the charged-current mediated D-s(+) and D+->phi pi(+)->mu(+)mu(-)pi(+) final states with significance greater than 4 standard deviations above background for the D+ state. We search for the continuum neutral-current decay of D+->pi(+)mu(+)mu(-) in the dimuon invariant mass spectrum away from the phi resonance. We see no evidence of signal above background and set a limit of B(D+->pi(+)mu(+)mu(-))< 3.9 x 10(-6) at the 90% C.L. This limit places the most stringent constraint on new phenomena in the c -> u mu(+)mu(-) transition.
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| 18. |
- Abazov, V. M., et al.
(author)
-
Search for Higgs bosons decaying to tau pairs in p(p)over-bar collisions with the D0 detector
- 2008
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 101:7, s. 071804-:101, s. 071804-
-
Journal article (peer-reviewed)abstract
- 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.
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| 19. |
- Abazov, V. M., et al.
(author)
-
Search for large extra dimensions via single photon plus missing energy final states at root s=1.96 TeV
- 2008
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 101:1, s. 011601-:101, s. 011601-
-
Journal article (peer-reviewed)abstract
- 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.
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| 20. |
- Abazov, V. M., et al.
(author)
-
Search for pair production of doubly charged Higgs bosons in the H++H--->mu(+)mu(+)mu(-)mu(-) final state
- 2008
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 101:7, s. 071803-:101, s. 071803-
-
Journal article (peer-reviewed)abstract
- 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.
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