| 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
-
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. |
- Aaltonen, T., et al.
(författare)
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Combination of CDF and D0 W-Boson mass measurements
- 2013
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:5, s. 052018-
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Tidskriftsartikel (refereegranskat)abstract
- We summarize and combine direct measurements of the mass of the W boson in root s = 1.96 TeV proton-antiproton collision data collected by CDF and D0 experiments at the Fermilab Tevatron Collider. Earlier measurements from CDF and D0 are combined with the two latest, more precise measurements: a CDF measurement in the electron and muon channels using data corresponding to 2.2 fb(-1) of integrated luminosity, and a D0 measurement in the electron channel using data corresponding to 4.3 fb(-1) of integrated luminosity. The resulting Tevatron average for the mass of the W boson is M-W = 80387 +/- 16 MeV. Including measurements obtained in electron-positron collisions at LEP yields the most precise value of M-W = 80385 +/- 15 MeV.
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| 4. |
- Aaltonen, T., et al.
(författare)
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Higgs boson studies at the Tevatron
- 2013
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:5, s. 052014-
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Tidskriftsartikel (refereegranskat)abstract
- We combine searches by the CDF and D0 Collaborations for the standard model Higgs boson with mass in the range 90-200 GeV/c(2) produced in the gluon-gluon fusion, WH, ZH, t (t) over barH, and vector boson fusion processes, and decaying in the H -> b (b) over bar, H -> W+W-, H -> ZZ, H -> tau(+)tau(-), and H -> gamma gamma modes. The data correspond to integrated luminosities of up to 10 fb(-1) and were collected at the Fermilab Tevatron in p (p) over bar collisions at root s = 1.96 TeV. The searches are also interpreted in the context of fermiophobic and fourth generation models. We observe a significant excess of events in the mass range between 115 and 140 GeV/c(2). The local significance corresponds to 3.0 standard deviations at m(H) = 125 GeV/c(2), consistent with the mass of the Higgs boson observed at the LHC, and we expect a local significance of 1.9 standard deviations. We separately combine searches for H -> b (b) over bar, H -> W+W-, H -> tau(+)tau(-), and H -> gamma gamma. The observed signal strengths in all channels are consistent with the presence of a standard model Higgs boson with a mass of 125 GeV/c(2).
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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 angular correlations of jets at s=1.96 TeV and determination of the strong coupling at high momentum transfers
- 2012
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 718:1, s. 56-63
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Tidskriftsartikel (refereegranskat)abstract
- We present a measurement of the average value of a new observable at hadron colliders that is sensitive to QCD dynamics and to the strong coupling constant, while being only weakly sensitive to parton distribution functions. The observable measures the angular correlations of jets and is defined as the number of neighboring jets above a given transverse momentum threshold which accompany a given jet within a given distance δR in the plane of rapidity and azimuthal angle. The ensemble average over all jets in an inclusive jet sample is measured and the results are presented as a function of transverse momentum of the inclusive jets, in different regions of δR and for different transverse momentum requirements for the neighboring jets. The measurement is based on a data set corresponding to an integrated luminosity of 0.7 fb -1 collected with the D0 detector at the Fermilab Tevatron Collider in pp- collisions at s=1.96 TeV. The results are well described by a perturbative QCD calculation in next-to-leading order in the strong coupling constant, corrected for non-perturbative effects. From these results, we extract the strong coupling and test the QCD predictions for its running over a range of momentum transfers of 50-400 GeV.
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| 7. |
- Abazov, V. M., et al.
(författare)
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Measurement of leptonic asymmetries and top-quark polarization in t(t)over-bar production
- 2013
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 87:1, s. 011103-
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Tidskriftsartikel (refereegranskat)abstract
- We present measurements of lepton (l) angular distributions in top-quark (t) pair production and t (t) over bar -> W(+)bW-(b) over bar -> l(+) vbl-(v) over bar(b) over bar decays produced in p (p) over bar collisions at a center-of-mass energy of root s = 1.96 TeV, where l is an electron or muon. Using data corresponding to an integrated luminosity of 5.4 fb(-1), collected with the D0 detector at the Fermilab Tevatron Collider, we measure for the first time the leptonic forward-backward asymmetry in dilepton final states and obtain A(FB)(l) = (5.8 +/- 5.1(stat) +/- 1.3(syst))%, corrected for detector acceptance. This is compared to the standard model prediction of A(FB)(l)(predicted) = (4.7 +/- 0.1)%. A deviation from the standard model prediction as previously seen in a D0 measurement based on the analysis of the l + jets final state is not observed in these dilepton final states. The two results differ from each other by 1.4 standard deviations and are combined to obtain A(FB)(l) = (11.8 +/- 3.2)%. Furthermore, we present a first study of the top-quark polarization.
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| 8. |
- Abazov, V. M., et al.
(författare)
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Measurement of the Semileptonic Charge Asymmetry using B-S(0) -> D-s mu X Decays
- 2013
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 110:1, s. 011801-
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Tidskriftsartikel (refereegranskat)abstract
- We present a measurement of the time-integrated flavor-specific semileptonic charge asymmetry in the decays of B-s(0) mesons that have undergone flavor mixing, a(sl)(s), using B-s(0)((B) over bar (0)(s)) -> D-s(-/+) mu(+/-) X decays, with D-s(-/+) -> phi pi(-/+) and phi -> K+K-, using 10.4 fb(-1) of proton-antiproton collisions collected by the D0 detector during Run II at the Fermilab Tevatron Collider. A fit to the difference between the time-integrated D0 detector during Run II at the Fermilab Tevatron Colllider. A fit to the difference between the time-integrated D-s(-) and D-s(+) mass distributions of the B-s(0) and ($) over bar (0)(s) candidates yields the flavor-specific asymmetry a(sl)(s) = [-1.12 +/- 0.74(stat) +/- 0.17(syst)]%, which is the most precise measurement and in agreement with the standard model prediction.
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| 9. |
- Abazov, V. M., et al.
(författare)
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Search for Higgs boson production in oppositely charged dilepton and missing energy events in p(p)over-bar collisions at root s=1.96 TeV
- 2012
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 86:3, s. 032010-
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Tidskriftsartikel (refereegranskat)abstract
- We present a search for the standard model Higgs boson using events with two oppositely charged leptons and large missing transverse energy as expected in H -> WW decays. The events are selected from data corresponding to 8.6 fb(-1) of integrated luminosity in p (p) over bar collisions at root s = 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. No significant excess above the standard model background expectation in the Higgs boson mass range this search is sensitive to is observed, and upper limits on the Higgs boson production cross section are derived.
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| 10. |
- Abazov, V. M., et al.
(författare)
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Search for the Standard Model Higgs Boson in Associated WH Production in 9.7 fb(-1) of p(p)over-bar Collisions with the D0 Detector
- 2012
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 109:12, s. 121804-
-
Tidskriftsartikel (refereegranskat)abstract
- We present a search for the standard model Higgs boson in final states with a charged lepton (electron or muon), missing transverse energy, and two or three jets, at least one of which is identified as a b-quark jet. The search is primarily sensitive to WH -> lvb (b) over bar production and uses data corresponding to 9.7 fb(-1) of integrated luminosity collected with the D0 detector at the Fermilab Tevatron p (p) over bar Collider at root s = 1.96 TeV. We observe agreement between the data and the expected background. For a Higgs boson mass of 125 GeV, we set a 95% C.L. upper limit on the production of a standard model Higgs boson of 5.2 x sigma(SM), where sigma(SM) is the standard model Higgs boson production cross section, while the expected limit is 4: 7 x sigma(SM).
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