| 41. |
- Abazov, V. M., et al.
(författare)
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Measurement of the Lambda(0)(b) lifetime in the exclusive decay Lambda(0)(b) -> J/psi Lambda(0) in p(p)over-bar collisions at root s=1.96 TeV
- 2012
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 85:11, s. 112003-
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Tidskriftsartikel (refereegranskat)abstract
- We measure the Lambda(0)(b) lifetime in the fully reconstructed decay Lambda(0)(b) -> J/psi Lambda(0) using 10.4 fb(-1) of p (p) over bar collisions collected with the D0 detector at root s = 1.96 TeV. The lifetime of the topologically similar decay channel B-0 -> J/psi K-S(0) is also measured. We obtain tau(Lambda(0)(b)) = 1.303 +/- 0.075(stat) +/- 0.035(syst) ps and tau(B-0) = 1.508 +/- 0.025(stat) +/- 0.043(syst) ps. Using these measurements, we determine the lifetime ratio of tau(Lambda(0)(b))/tau(B-0) = 0.864 +/- 0.052(stat) +/- 0.033(syst).
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| 42. |
- Abazov, V. M., et al.
(författare)
-
Measurement of the semileptonic charge asymmetry in B-0 meson mixing with the D0 detector
- 2012
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 86:7, s. 072009-
-
Tidskriftsartikel (refereegranskat)abstract
- We present a measurement of the semileptonic mixing asymmetry for B-0 mesons, a(sl)(d), using two independent decay channels: B-0 -> mu+D-X, with D- ->! K+ pi(-) pi(-); and B-0 -> mu+D*X-, with D*(-) -> (D) over bar (0) pi(-), (D) over bar (-)(0) K+ pi(-) (and charge conjugate processes). We use a data sample corresponding to 10.4 fb(-1) of p (p) over bar collisions at root s = 1.96 TeV, collected with the D0 experiment at the Fermilab Tevatron collider. We extract the charge asymmetries in these two channels as a function of the visible proper decay length of the B-0 meson, correct for detector-related asymmetries using data-driven methods, and account for dilution from charge-symmetric processes using Monte Carlo simulation. The final measurement combines four signal visible proper decay length regions for each channel, yielding a(sl)(d) = [0.68 +/- 0: 45(stat) +/- 0.14(syst)]%. This is the single most precise measurement of this parameter, with uncertainties smaller than the current world average of B factory measurements.
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| 43. |
- Abazov, V. M., et al.
(författare)
-
Measurement of the t(t)over-bar production cross section in p(p)over-bar collisions at root s=1.96 TeV in dilepton final states
- 2005
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 626, s. 55-64
-
Tidskriftsartikel (refereegranskat)abstract
- We present a measurement of the top quark pair (a) production cross section in pp collisions at root s = 1.96 TeV using events with two charged leptons in the final state. This analysis utilizes an integrated luminosity of 224-243 pb(-1) collected with the DO detector at the Fermilab Tevatron Collider. We observe 13 events in the e(+)e(-), e mu and mu(+)mu(-) channels with an expected background of 3.2 +/- 0.7 events. For a top quark mass of 175 GeV, we measure a t (t) over bar production cross section of sigma(t (t) over bar) = 8.6(-2.7)(+3.2) (stat) +/- 1.1(syst) +/- 0.6(lumi) pb, consistent with the standard model prediction.
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| 44. |
- Abazov, V. M., et al.
(författare)
-
Precision Measurement of the Top Quark Mass in Lepton plus Jets Final States
- 2014
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 113:3, s. 032002-
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Tidskriftsartikel (refereegranskat)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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| 45. |
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| 46. |
- Abazov, V. M., et al.
(författare)
-
Search for squarks and gluinos in events with jets and missing transverse energy in p(p)over-bar collisions at root s-=1.96 TeV
- 2006
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 638:2-3, s. 119-127
-
Tidskriftsartikel (refereegranskat)abstract
- The results of a search for squarks and gluinos using data from p (p) over bar collisions recorded at a center-of-mass energy of 1.96 TeV by the DO detector at the Fermilab Tevatron Collider are reported. The topologies analyzed consist of acoplanar-jet and multijet events with large missing transverse energy. No evidence for the production of squarks or gluinos was found in a data sample of 310pb(-1). Lower limits of 325 and 241 GeV were derived at the 95% C.L. on the squark and gluino masses, respectively, within the framework of minimal supergravity with tan beta=3, A(0) = 0, and mu < 0.
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| 47. |
- Abazov, V. M., et al.
(författare)
-
Search for the Standard Model Higgs Boson in ZH -> l(+) l(-) b(b)over-bar Production with the D0 Detector in 9.7 fb(-1)of p(p)over-bar Collisions at root s=1.96 TeV
- 2012
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 109:12, s. 121803-
-
Tidskriftsartikel (refereegranskat)abstract
- We present a search for the standard model (SM) Higgs boson produced in association with a Z boson in 9.7 fb(-1) of p (p) over bar collisions collected with the D0 detector at the Fermilab Tevatron Collider at root s = 1.96 TeV. Selected events contain one reconstructed Z -> e(+) e(-) or Z -> mu(+) mu(-)candidate and at least two jets, including at least one jet identified as likely to contain a b quark. To validate the search procedure, we also measure the cross section for ZZ production in the same final state. It is found to be consistent with its SM prediction. We set upper limits on the ZH production cross section times branching ratio for H -> b (b) over bar at the 95% C.L. for Higgs boson masses 90 <= M-H <= 150 GeV. The observed (expected) limit for M-H = 125 GeV is 7.1 (5.1) times the SM cross section.
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| 48. |
- Abazov, V. M., et al.
(författare)
-
Study of direct CP violation in B-+/--> J/psi K-+/-(pi(+/-)) decays
- 2008
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 100:21, s. 211802-
-
Tidskriftsartikel (refereegranskat)abstract
- We present a search for direct CP violation in B-+/- -> J/psi K-+/- (pi(+/-)) decays. The event sample is selected from 2: 8 fb(-1) of p (p) over bar collisions recorded by D0 experiment in run II of the Fermilab Tevatron Collider. The charge asymmetry A(CP)(B+ -> J/psi K+) = +0: 0075 +/- 0: 0061(stat) +/- 0: 0030 (syst) is obtained using a sample of approximately 40 000 B-+/- -> J/psi K-+/- decays. The achieved precision is of the same level as the expected deviation predicted by some extensions of the standard model. We also measured the charge asymmetry A(CP) (B+ -> J/psi pi(+)) = - 0: 09 +/- 0: 08(stat) +/- 0: 03(syst).
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| 49. |
- Abazov, V. M., et al.
(författare)
-
W gamma Production and Limits on Anomalous WW gamma Couplings in p(p)over-bar Collisions at root s=1.96 TeV
- 2011
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 107:24, s. 241803-
-
Tidskriftsartikel (refereegranskat)abstract
- We measure the cross section and the difference in rapidities between photons and charged leptons for inclusive W(-> l nu) + gamma production in e gamma and mu gamma final states. Using data corresponding to an integrated luminosity of 4.2 fb(-1) collected with the D0 detector at the Fermilab Tevatron Collider, the measured cross section times branching fraction for the process p (p) over bar -> W gamma + X -> l nu gamma + X and the distribution of the charge-signed photon-lepton rapidity difference are found to be in agreement with the standard model. These results provide the most stringent limits on anomalous WW gamma couplings for data from hadron colliders: -0.4 < Delta kappa(gamma) < 0.4 and -0.08 < lambda(gamma) < 0.07 at the 95% C.L.
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| 50. |
- Abazov, V. M., et al.
(författare)
-
Evidence for the Decay B-s(0)->(DsDs(*))-D-(*) and a Measurement of Delta Gamma(CP)(s)/Gamma(s)
- 2009
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 102:9, s. 091801-
-
Tidskriftsartikel (refereegranskat)abstract
- We search for the semi-inclusive process B-s(0)->(DsDs(*))-D-(*) using 2.8 fb(-1) of pp collisions at s=1.96 TeV recorded by the D0 detector operating at the Fermilab Tevatron Collider. We observe 26.6 +/- 8.4 signal events with a significance above background of 3.2 standard deviations yielding a branching ratio of B(B-s(0)->(DsDs(*))-D-(*))=0.035 +/- 0.010(stat.)+/- 0.011(syst.). Under certain theoretical assumptions, these double-charm final states saturate CP-even eigenstates in the B-s(0) decays resulting in a width difference of Delta Gamma(CP)(s)/Gamma(s)=0.072 +/- 0.021(stat.)+/- 0.022(syst.).
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