1. |
- Aad, G., et al.
(creator_code:aut_t)
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- 2011
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swepub:Mat__t (swepub:level_refereed_t)
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2. |
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- 2017
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record:In_t: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:2
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swepub:Mat_article_t (swepub:level_refereed_t)
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3. |
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4. |
- Aaltonen, T., et al.
(creator_code:aut_t)
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Combination of CDF and D0 measurements of the W boson helicity in top quark decays
- 2012
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record:In_t: Physical Review D. - 1550-7998 .- 1550-2368. ; 85:7, s. 071106-
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swepub:Mat_article_t (swepub:level_refereed_t)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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5. |
- Abazov, V. M., et al.
(creator_code:aut_t)
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Evidence for production of single top quarks and first direct measurement of vertical bar V-tb vertical bar
- 2007
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record:In_t: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 98:18, s. 181802-
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swepub:Mat_article_t (swepub:level_refereed_t)abstract
- The D0 Collaboration presents first evidence for the production of single top quarks at the Fermilab Tevatron < p(p)over bar > collider. Using a 0.9 fb(-1) dataset, we apply a multivariate analysis to separate signal from background and measure sigma(< p(p)over bar >-> tb+X,tqb+X)=4.9 +/- 1.4 pb. The probability to measure a cross section at this value or higher in the absence of a signal is 0.035%, corresponding to a 3.4 standard deviation significance. We use the cross section measurement to directly determine the Cabibbo-Kobayashi-Maskawa matrix element that describes the Wtb coupling and find 0.68 <= 1 at 95% C.L. within the standard model.
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6. |
- Abazov, V. M., et al.
(creator_code:aut_t)
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Lifetime difference and CP-violating phase in the B-s(0) system
- 2007
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record:In_t: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 98:12, s. 121801-
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swepub:Mat_article_t (swepub:level_refereed_t)abstract
- From an analysis of the decay B-s(0)-> J/psi phi, we obtain the width difference between the light and heavy mass eigenstates Delta Gamma equivalent to(Gamma(L)-Gamma(H))=0.17 +/- 0.09(stat)+/- 0.02(syst) ps(-1) and the CP-violating phase phi(s)=-0.79 +/- 0.56(stat)(-0.01)(+0.14)(syst). Under the hypothesis of no CP violation (phi(s)equivalent to 0), we obtain 1/Gamma=tau/(B-s(0))=1.52 +/- 0.08(stat)(-0.03)(+0.01)(syst) ps and Delta Gamma=0.12(-0.10)(+0.08)(stat)+/- 0.02(syst) ps(-1). The data sample corresponds to an integrated luminosity of about 1.1 fb(-1) accumulated with the D0 detector at the Fermilab Tevatron collider. This is the first direct measurement of the CP-violating mixing phase in the B-s(0) system.
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7. |
- Abazov, V. M., et al.
(creator_code:aut_t)
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Measurement of the Angular and Lifetime Parameters of the Decays B-d(0) -> J/psi K*(0) and B-s(0) -> J/psi phi
- 2009
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record:In_t: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 102:3, s. 032001-:102, s. 032001-
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swepub:Mat_article_t (swepub:level_refereed_t)abstract
- We present measurements of the linear polarization amplitudes and the strong relative phases that describe the flavor-untagged decays B-d(0) --> J/psi K*(0) and B-s(0) --> J/psi phi in the transversity basis. We also measure the mean lifetime (tau) over bar (s) of the B-s(0) mass eigenstates and the lifetime ratio (tau) over bar (s)/tau(d). The analyses are based on approximately 2.8 fb(-1) of data recorded with the D0 detector. From our measurements of the angular parameters we conclude that there is no evidence for a deviation from flavor SU( 3) symmetry for these decays and that the factorization assumption is not valid for the B-d(0) --> J/psi K*(0) decay.
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8. |
- Abazov, V. M., et al.
(creator_code:aut_t)
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Observation of ZZ Production in p(p)over-bar Collisions at root s=1.96 TeV
- 2008
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record:In_t: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 101:17, s. 171803-:101, s. 171803-
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swepub:Mat_article_t (swepub:level_refereed_t)abstract
- 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.
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9. |
- Abazov, V. M., et al.
(creator_code:aut_t)
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Search for Associated W and Higgs Boson Production in p(p)over-bar Collisions at root s=1.96 TeV
- 2009
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record:In_t: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 102:5, s. 051803-:102, s. 051803-
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swepub:Mat_article_t (swepub:level_refereed_t)abstract
- We present results of a search for WH -> l nu b (b) over bar production in p (p) over bar collisions based on the analysis of 1.05 fb(-1) of data collected by the D0 experiment at the Fermilab Tevatron, using a neural network for separating the signal from backgrounds. No signal-like excess is observed, and we set 95% C. L. upper limits on the WH production cross section multiplied by the branching ratio for H -> b (b) over bar for Higgs boson masses between 100 and 150 GeV. For a mass of 115 GeV, we obtain an observed (expected) limit of 1.5 (1.4) pb, a factor of 11.4 (10.7) times larger than the standard model prediction.
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10. |
- Abazov, V. M., et al.
(creator_code:aut_t)
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Search for single production of scalar leptoquarks in p(p)over-bar collisions decaying into muons and quarks with the D0 detector
- 2007
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record:In_t: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 647:2-3, s. 74-81
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swepub:Mat_article_t (swepub:level_refereed_t)abstract
- lWe report on a search for second generation leptoquarks (LQ(2)) which decay into a muon plus quark in (p) over barp collisions at a center-of-mass energy of root s = 1.96 TeV in the DO detector using an integrated luminosity of about 300 pb(-1). No evidence for a leptoquark signal is observed and an upper bound on the product of the cross section for single leptoquark production times branching fraction into a quark and a muon was determined for second generation scalar leptoquaiks as a function of the leptoquark mass. This result has been combined with a previously published DO search for leptoquark pair production to obtain leptoquark mass limits as a function of the leptoquark-muon-quark coupling, lambda. Assuming lambda = 1, lower limits on the mass of a second generation scalar leptoquark coupling to a u quark and a muon are m(LQ2) > 274 GeV and m(LQ2) > 226 GeV for beta = 1 and beta = 1/2, respectively.
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