| 11. |
- Abazov, V. M., et al.
(author)
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Measurement of the Direct CP-violating Charge Asymmetry in D-s(+/-) -> Phi pi(+/-) Decays
- 2014
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 112:11, s. 111804-
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Journal article (peer-reviewed)abstract
- We present a measurement of the direct CP-violating charge asymmetry in D-s(+) -> phi pi(+/-) decays where the phi meson decays to K+ K-, using the full Run II data set with an integrated luminosity of 10.4 fb(-1) of proton- antiproton collisions collected using the D0 detector at the Fermilab Tevatron Collider. The normalized difference A(CP) in the yield of D-s(+) and D-s(-) mesons in these decays is measured by fitting the difference between their reconstructed invariant mass distributions. This results in an asymmetry of A(CP) = [-0.38 +/- 0.27]%, which is the most precise measurement of this quantity to date. The result is consistent with the standard model prediction of zero CP asymmetry in this decay.
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| 12. |
- Abazov, V. M., et al.
(author)
-
Measurement of the direct CP-violating parameter A(CP) in the decay D+ -> K-pi(+)pi(+)
- 2014
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 90:11, s. 111102-
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Journal article (peer-reviewed)abstract
- We measure the direct CP-violating parameter A(CP) for the decay of the charged charm meson, D+ -> K-pi(+)pi(+)(and charge conjugate), using the full 10.4 fb(-1) sample of p (p) over bar collisions at root s = 1.96 TeV collected by the D0 detector at the Fermilab Tevatron collider. We extract the raw reconstructed charge asymmetry by fitting the invariant mass distributions for the sum and difference of charge-specific samples. This quantity is then corrected for detector-related asymmetries using data-driven methods and for possible physics asymmetries (from B. D processes) using input from Monte Carlo simulation. We measure A(CP) =[-0.16 +/- 0.15(stat) +/- 0.09(syst)] %, which is consistent with zero, as expected from the standard model prediction of CP conservation, and is the most precise measurement of this quantity to date.
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| 13. |
- Abazov, V. M., et al.
(author)
-
Measurement of the electric charge of the top quark in t(t)over-bar events
- 2014
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 90:5, s. 051101-
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Journal article (peer-reviewed)abstract
- We present a measurement of the electric charge of top quarks using t (t) over bar events produced in p (p) over bar collisions at the Tevatron. The analysis is based on fully reconstructed t (t) over bar pairs in lepton + jets final states. Using data corresponding to 5.3 fb(-1) of integrated luminosity, we exclude the hypothesis that the top quark has a charge of Q = -4/3e at a significance greater than 5 standard deviations. We also place an upper limit of 0.46 on the fraction of such quarks that can be present in an admixture with the standard model top quarks (Q = +2/3e) at a 95% confidence level.
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| 14. |
- Abazov, V. M., et al.
(author)
-
Measurement of the forward-backward asymmetry in the distribution of leptons in t(t)over-bar events in the lepton plus jets channel
- 2014
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 90:7, s. 072001-
-
Journal article (peer-reviewed)abstract
- We present measurements of the forward-backward asymmetry in the angular distribution of leptons from decays of top quarks and antiquarks produced in proton-antiproton collisions. We consider the final state containing a lepton and at least three jets. The entire sample of data collected by the D0 experiment during Run II of the Fermilab Tevatron Collider, corresponding to 9.7 fb(-1) of integrated luminosity, is used. The asymmetry measured for reconstructed leptons is A(FB)(l) = (2.9 +/- 2.1(stat.)(-1.7)(+1.5) (syst.))%. When corrected for efficiency and resolution effects within the lepton rapidity coverage of vertical bar y(l)vertical bar < 1.5, the asymmetry is found to be A(FB)(l) = (4.2 +/- 2.3(stat.)(-2.0)(+1.7) (syst.))%. We examine the dependence of A(FB)(l) on the transverse momentum and rapidity of the lepton. Combination with the asymmetry measured in the final states containing two leptons yields A(FB)(l) = (4.2 +/- 2.0(stat.) +/- 1.4(syst.))%. The results are in agreement with predictions from the next-to-leading-order QCD generator MC@NLO, which predicts an asymmetry of A(FB)(l) = 2.0% for vertical bar y(l)vertical bar < 1.5.
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| 15. |
- Abazov, V. M., et al.
(author)
-
Measurement of the forward-backward asymmetry in top quark-antiquark production in p(p)over-bar collisions using the lepton plus jets channel
- 2014
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 90:7
-
Journal article (peer-reviewed)abstract
- We present a measurement of the forward-backward asymmetry in top quark-antiquark production using the full Tevatron Run II data set collected by the D0 experiment at Fermilab. The measurement is performed in lepton + jets final states using a new kinematic fitting algorithm for events with four or more jets and a new partial reconstruction algorithm for events with only three jets. Corrected for detector acceptance and resolution effects, the asymmetry is evaluated to be A(FB) = (10.6 +/- 3.0)%. Results are consistent with the standard model predictions which range from 5.0% to 8.8%. We also present the dependence of the asymmetry on the invariant mass of the top quark-antiquark system and the difference in rapidities of the top quark and antiquark.
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| 16. |
- Abazov, V. M., et al.
(author)
-
Measurement of the W boson mass with the D0 detector
- 2014
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 89:1, s. 012005-
-
Journal article (peer-reviewed)abstract
- We give a detailed description of the measurement of the W boson mass, M-W, performed on an integrated luminosity of 4.3 fb(-1), which is based on similar techniques as used for our previous measurement done on an independent data set of 1 fb(-1) of data. The data were collected using the D0 detector at the Fermilab Tevatron Collider. This data set yields 1.68 x 10(6) W -> ev candidate events. We measure the mass using the transverse mass, electron transverse momentum, and missing transverse energy distributions. The M-W measurements using the transverse mass and the electron transverse momentum distributions are the most precise of these three and are combined to give M-W 80.367 +/- 0.013 (stat) +/- 0.022(syst) GeV = 80: 367 +/- 0.026 GeV. When combined with our earlier measurement on 1 fb(-1) of data, we obtain M-W = 80.375 +/- 0.023 GeV.
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| 17. |
- Abazov, V. M., et al.
(author)
-
Measurement of the W Boson Production Charge Asymmetry in p(p)over-bar -> W plus X -> ev plus X Events at root s=1.96 Tev
- 2014
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 112:15, s. 151803-
-
Journal article (peer-reviewed)abstract
- We present a measurement of the W boson production charge asymmetry in p (p) over bar -> W + X -> ev + X events at a center of mass energy of 1.96 TeV, using 9.7 fb(-1) of integrated luminosity collected with the D0 detector at the Fermilab Tevatron Collider. The neutrino longitudinal momentum is determined by using a neutrino weighting method, and the asymmetry is measured as a function of the W boson rapidity. The measurement extends over wider electron pseudorapidity region than previous results and is the most precise to date, allowing for precise determination of proton parton distribution functions in global fits.
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| 18. |
- Abazov, V. M., et al.
(author)
-
Muon reconstruction and identification with the Run II D0 detector
- 2014
-
In: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 737, s. 281-294
-
Journal article (peer-reviewed)abstract
- We present an overview of the muon reconstruction and identification methods employed by the DO collaboration to analyze the Run II (2001-2011) p (p) over bar data of the Fermilab Tevatron collider at root s = 1.96 TeV. We discuss the performance of these methods, how it is measured using DO data, and how it is properly modeled by the DO simulation program. In its pseudorapidity acceptance, vertical bar eta vertical bar < 2, the muon system identifies high-p(T) muons (p(T) greater than or similar to 10 GeV) with efficiencies ranging from 72% to 89%. Muons tracks are reconstructed in the DO central tracking system with efficiencies ranging from 85% to 92% and with a typical relative momentum resolution of 10% for p(T) = 40 GeV. Isolation criteria reject multijet background with efficiencies of 87-99%.
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| 19. |
- Abazov, V. M., et al.
(author)
-
Observation and studies of double J/psi production at the Tevatron
- 2014
-
In: Physical Review D. - 1550-7998 .- 1550-2368. ; 90:11, s. 111101-
-
Journal article (peer-reviewed)abstract
- We present the observation of doubly produced J/psi mesons with the D0 detector at Fermilab in p (p) over bar collisions at root s = 1.96 TeV. The production cross section for both singly and doubly produced J/psi mesons is measured using a sample with an integrated luminosity of 8.1 fb(-1). For the first time, the double J/psi production cross section is separated into contributions due to single and double parton scatterings. Using these measurements, we determine the effective cross section seff, a parameter characterizing an effective spatial area of the parton-parton interactions and related to the parton spatial density inside the nucleon.
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| 20. |
- Abazov, V. M., et al.
(author)
-
Precision Measurement of the Top Quark Mass in Lepton plus Jets Final States
- 2014
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 113:3, s. 032002-
-
Journal article (peer-reviewed)abstract
- We measure the mass of the top quark in lepton + jets final states using the full sample of p (p) over bar collision data collected by the D0 experiment in Run II of the Fermilab Tevatron Collider at root s = 1.96 TeV, corresponding to 9.7 fb(-1) of integrated luminosity. We use a matrix element technique that calculates the probabilities for each event to result from t (t) over bar production or background. The overall jet energy scale is constrained in situ by the mass of theW boson. We measure m(t) = 174.98 +/- 0.76 GeV. This constitutes the most precise single measurement of the top-quark mass.
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