| 1. |
- Aaltonen, T., et al.
(författare)
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Evidence for a Particle Produced in Association with Weak Bosons and Decaying to a Bottom-Antibottom Quark Pair in Higgs Boson Searches at the Tevatron
- 2012
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 109:7, s. 071804-
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Tidskriftsartikel (refereegranskat)abstract
- We combine searches by the CDF and D0 Collaborations for the associated production of a Higgs boson with a W or Z boson and subsequent decay of the Higgs boson to a bottom-antibottom quark pair. The data, originating from Fermilab Tevatron p (p) over bar collisions at root s = 1.96 TeV, correspond to integrated luminosities of up to 9.7 fb(-1). The searches are conducted for a Higgs boson with mass in the range 100-150 GeV/c(2). We observe an excess of events in the data compared with the background predictions, which is most significant in the mass range between 120 and 135 GeV/c(2). The largest local significance is 3.3 standard deviations, corresponding to a global significance of 3.1 standard deviations. We interpret this as evidence for the presence of a new particle consistent with the standard model Higgs boson, which is produced in association with a weak vector boson and decays to a bottom-antibottom quark pair.
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| 2. |
- Aaltonen, T., et al.
(författare)
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Combination of CDF and D0 measurements of the W boson helicity in top quark decays
- 2012
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 85:7, s. 071106-
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Tidskriftsartikel (refereegranskat)abstract
- We report the combination of recent measurements of the helicity of the W boson from top quark decay by the CDF and D0 collaborations, based on data samples corresponding to integrated luminosities of 2.7-5.4 fb(-1) of p (p) over bar collisions collected during Run II of the Fermilab Tevatron collider. Combining measurements that simultaneously determine the fractions of W bosons with longitudinal (f(0)) and right-handed (f(+)) helicities, we find f(0) = 0.722 +/- 0.081[+/- 0.062(stat) +/- 0.052(syst)] and f(+) = -0.033 +/- 0.046[+/- 0.034(stat) +/- 0.031(syst)]. Combining measurements where one of the helicity fractions is fixed to the value expected in the standard model, we find f(0) = 0.682 +/- 0.057[+/- 0.035(stat) +/- 0.046(syst)] for fixed f(+) and f(+) = -0.015 +/- 0.035[+/- 0.018(stat) +/- 0.030(syst)] for fixed f(0). The results are consistent with standard model expectations.
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| 3. |
- Abazov, V. M., et al.
(författare)
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Model indedpendent search for new phenomena in p(p)over-bar collisions at root s=1.96 TeV
- 2012
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 85:9, s. 092015-
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Tidskriftsartikel (refereegranskat)abstract
- We describe a model-independent search for physics beyond the standard model in lepton final states. We examine 117 final states using 1.1 fb(-1) of p (p) over bar collisions data at root s = 1.96 TeV collected with the D0 detector. We conclude that all observed discrepancies between data and model can be attributed to uncertainties in the standard model background modeling, and hence we do not see any evidence for physics beyond the standard model.
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| 4. |
- Abazov, V. M., et al.
(författare)
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Search for the standard model Higgs boson in the ZH -> nu(nu)over-barb(b)over-bar channel in 9.5 fb(-1) of p(p)over-bar collisions at root s=1.96 TeV
- 2012
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 716:2, s. 285-293
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Tidskriftsartikel (refereegranskat)abstract
- We present a search for the standard model Higgs boson in 9.5 fb(-1) of p (p) over bar collisions at root s = 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. The final state considered contains a pair of b jets and is characterized by an imbalance in transverse energy, as expected from p (p) over bar -> ZH -> nu(nu) over barb (b) over bar production. The search is also sensitive to the WH -> l nu b (b) over bar channel when the charged lepton is not identified. The data are found to be in good agreement with the expected background. For a Higgs boson mass of 125 GeV, we set a limit at the 95% C.L. on the cross section sigma(p (p) over bar -> vertical bar Z/W vertical bar H), assuming standard model branching fractions, that is a factor of 4.3 times larger than the theoretical standard model value, while the expected factor is 3.9. The search is also used to measure a combined WZ and ZZ production cross section that is a factor of 0.94 +/- 0.31 (stat) +/- 0.34 (syst) times the standard model prediction of 4.4 pb, with an observed significance of 2.0 standard deviations. (C) 2012 Elsevier B.V. All rights reserved.
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| 5. |
- Abazov, V. M., et al.
(författare)
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Combined Search for the Standard Model Higgs Boson Decaying to b(b)over-bar Using the D0 Run II Data Set
- 2012
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 109:12, s. 121802-
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of the combination of searches for the standard model Higgs boson produced in association with a W or Z boson and decaying into b (b) over bar using the data sample collected with the D0 detector in p (p) over bar collisions at root s = 1.96 TeV at the Fermilab Tevatron Collider. We derive 95% C.L. upper limits on the Higgs boson cross section relative to the standard model prediction in the mass range 100 GeV <= M-H <= 150 GeV, and we exclude Higgs bosons with masses smaller than 102 GeV at the 95% C.L. In the mass range 120 GeV <= M-H <= 145 GeV, the data exhibit an excess above the background prediction with a global significance of 1.5 standard deviations, consistent with the expectation in the presence of a standard model Higgs boson.
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| 6. |
- Abazov, V. M., et al.
(författare)
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Measurement of the CP-violating phase phi sJ/psi phi using the flavor-tagged decay Bs(0) -> J/psi phi in 8 fb(-1) of p(p)over-bar collisions
- 2012
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 85:3, s. 032006-
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Tidskriftsartikel (refereegranskat)abstract
- We report an updated measurement of the CP-violating phase, phi(J/psi phi)(s), and the decay-width difference for the two mass eigenstates, Delta Gamma(s), from the flavor-tagged decay B-s(0) -> J/psi phi. The data sample corresponds to an integrated luminosity of 8.0 fb(-1) accumulated with the D0 detector using p (p) over bar collisions at root s = 1.96 TeV produced at the Fermilab Tevatron collider. The 68% Bayesian credibility intervals, including systematic uncertainties, are Delta Gamma(s) = 0.163(-0.064)(+0.065) ps(-1) and phi(J/psi phi)(s) = -0.55(-0.36)(+0.38). The p-value for the Standard Model point is 29.8%.
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| 7. |
- Abazov, V. M., et al.
(författare)
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Measurement of the inclusive jet cross section in p(p)over-bar collisions at root s=1.96 TeV
- 2012
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 85:5
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Tidskriftsartikel (refereegranskat)abstract
- We present a measurement of the inclusive jet cross section using the Run II cone algorithm and data collected by the D0 experiment in p (p) over bar collisions at a center-of-mass energy root s = 1.96 TeV, corresponding to an integrated luminosity of 0: 70 fb(-1). The jet energy calibration and the method used to extract the inclusive jet cross section are described. We discuss the main uncertainties, which are dominated by the jet energy scale uncertainty. The results cover jet transverse momenta from 50 GeV to 600 GeV with jet rapidities in the range -2.4 to 2.4 and are compared to predictions using recent proton parton distribution functions. Studies of correlations between systematic uncertainties in transverse momentum and rapidity are presented.
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| 8. |
- Abazov, V. M., et al.
(författare)
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Search for Charged Massive Long-Lived Particles
- 2012
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 108:12, s. 121802-
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Tidskriftsartikel (refereegranskat)abstract
- 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 p (p) over bar 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.
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| 9. |
- Abazov, V. M., et al.
(författare)
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Search for Doubly Charged Higgs Boson Pair Production in p(p)over-bar Collisions at root s=1.96 TeV
- 2012
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 108:2, s. 021801-
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Tidskriftsartikel (refereegranskat)abstract
- We present a search for pair production of doubly charged Higgs bosons in the processes q (q) over bar -> H(++)H(--) decaying through H(+/-+/-) ->tau(+/-)tau(+/-), mu(+/-)tau(+/-), mu(+/-)mu(+/-). The search is performed in p (p) over bar collisions at a center-of-mass energy of root s = 1:96 TeV using an integrated luminosity of up to 7:0 fb(-1) collected by the D0 experiment at the Fermilab Tevatron Collider. The results are used to set 95% C. L. limits on the pair production cross section of doubly charged Higgs bosons and on their mass for different H(+/-+/-) branching fractions. Models predicting different H(+/-+/-) decays are investigated. Assuming B(H(+/-+/-) -> tau(+/-)tau(+/-)) = 1 yields an observed (expected) lower limit on the mass of a left- handed H(L)(+/-+/-) boson of 128 (116) GeV and assuming B(H(+/-+/-) -> mu(+/-)tau(+/-)) = 1 the corresponding limits are 144 (149) GeV. In a model with B(H(+/-+/-) -> tau +/-tau(+/-) B(H(+/-+/-) -> mu(+/-)tau(+/-)) = B(H(+/-+/-) -> mu(+/-)mu(+/-) ) 1/3, we obtain M(H(L)(+/-+/-)) > 130 (138) GeV.
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| 10. |
- Abazov, V. M., et al.
(författare)
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Search for Higgs bosons decaying to tau(+)tau(-) pairs in p(p)over-bar collisions at root s=1.96 TeV
- 2012
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 707:3-4, s. 323-329
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Tidskriftsartikel (refereegranskat)abstract
- We present a search for the production of neutral Higgs bosons decaying into tau(+)tau(-) pairs in p (p) over bar collisions at a center-of-mass energy of 1.96 TeV. The data, corresponding to an integrated luminosity of 5.4 fb(-1), were collected by the DO experiment at the Fermilab Tevatron Collider. We set upper limits at the 95% C.L. on the product of production cross section and branching ratio for a scalar resonance decaying into tau(+)tau(-) pairs, and we interpret these limits as limits on the production of Higgs bosons in the minimal supersymmetric standard model (MSSM) and as constraints in the MSSM parameter space.
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