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Measurement Of The Pp̅ → Wz + X Cross Section At √S =1.96 Tev And Limits On Wwz Trilinear Gauge Couplings, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Measurement Of The Pp̅ → Wz + X Cross Section At √S =1.96 Tev And Limits On Wwz Trilinear Gauge Couplings, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Kenneth Bloom Publications
We present measurements of the process pp̅ → WZ + X → ℓ′νℓℓ&#; at √s = 1.96 TeV, where ℓ and ℓ′ are electrons or muons. Using 1 fb-1 of data from the D0 experiment, we observe 13 candidates with an expected background of 4.5 ± 0.6 events and measure a cross section σ(WZ) = 2.7-1.3+1.7 pb. From the number of observed events and the Z boson transverse momentum distribution, we limit the trilinear WWZ gauge couplings to -0.17 ≤ λZ ≤ 0.21(ΔκZ= 0) at the 95% C.L. for a form …
Study Of The Decay BS0 → DS(*)DS(*), V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Study Of The Decay BS0 → DS(*)DS(*), V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Kenneth Bloom Publications
We report a study of the decay Bs0 → Ds(*)Ds(*) using a data sample corresponding to 1.3 fb-1 of integrated luminosity collected by the D0 experiment in 2002–2006 during run II of the Fermilab Tevatron collider. One Ds(*) meson was partially reconstructed in the decay Ds→ φμν, and the other Ds(*) meson was identified using the decay Ds→ φπ where no attempt was made to distinguish Ds and Ds(*) states. For the branching fraction Br(Bs0 → Ds …
Measurement Of The Tt̅ Production Cross Section In Pp̅ Collisions At √S = 1.96 Tev Using Kinematic Characteristics Of Lepton + Jets Events, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Measurement Of The Tt̅ Production Cross Section In Pp̅ Collisions At √S = 1.96 Tev Using Kinematic Characteristics Of Lepton + Jets Events, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Kenneth Bloom Publications
We present a measurement of the top quark pair production cross section in pp̅ collisions at √s = 1.96 TeV utilizing 425 pb-1 of data collected with the D0 detector at the Fermilab Tevatron Collider. We consider the final state of the top quark pair containing one high-pT electron or muon and at least four jets. We exploit specific kinematic features of tt̅ events to extract the cross section. For a top quark mass of 175 GeV, we measure σ tt̅ = 6.4-1.2+1.3(stat) ± 0.7(syst) ± 0.4(lum) pb, in good agreement with the …
Search For Production Of Single Top Quarks Via Tcg And Tug Flavor-Changing-Neutral-Current Couplings, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Search For Production Of Single Top Quarks Via Tcg And Tug Flavor-Changing-Neutral-Current Couplings, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Kenneth Bloom Publications
We search for the production of single top quarks via flavor-changing-neutral-current couplings of a gluon to the top quark and a charm (c) or up (u) quark. We analyze 230 pb-1 of lepton + jets data from pp̅ collisions at a center of mass energy of 1.96 TeV collected by the D0 detector at the Fermilab Tevatron Collider. We observe no significant deviation from standard model predictions, and hence set upper limits on the anomalous coupling parameters κgc/Λ and κgu/Λ, where κg define the strength of tcg and …
Measurement Of The ΛB0 Lifetime Using Semileptonic Decays, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Measurement Of The ΛB0 Lifetime Using Semileptonic Decays, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Kenneth Bloom Publications
We report a measurement of the Λb0 lifetime using a sample corresponding to 1:3 fb-1 of data collected by the D0 experiment in 2002–2006 during run II of the Fermilab Tevatron collider. The Λb0 baryon is reconstructed via the decay Λb0 → μν&#; Λ c+X. Using 4437 ± 329 signal candidates, we measure the Λb0 lifetime to be τ(Λb0) = 1.290-0.110+0.119 (stat) -0.091+0.087(syst) ps, which is among the most precise measurements in semileptonic Λb0 decays. This result is in …
Search For Third-Generation Scalar Leptoquarks In Pp̅ Collisions At √S = 1.96 Tev, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Search For Third-Generation Scalar Leptoquarks In Pp̅ Collisions At √S = 1.96 Tev, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Kenneth Bloom Publications
We report on a search for charge-1/3 third-generation leptoquarks (LQ) produced in pp̅ collisions at √s = 1.96 TeV using the D0 detector at Fermilab. Third-generation leptoquarks are assumed to be produced in pairs and to decay to a tau neutrino and a b quark with branching fraction B. We place upper limits on (pp̅→ LQ L̅Q̅) B2 as a function of the leptoquark mass MLQ. Assuming B-1, we exclude at the 95% confidence level third-generation scalar leptoquarks with MLQ < 229 GeV.
Direct Observation Of The Strange B Baryon ΞB-, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Direct Observation Of The Strange B Baryon ΞB-, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Kenneth Bloom Publications
We report the first direct observation of the strange b baryon Ξb-( Ξb+). We reconstruct the decay Ξb- → J/ψΞ-, withJ/ψ → μ+ μ-, and Ξ- → Λ π - → p π-+ π+- in pp̅ collisions at √s = 1.96 TeV. Using 1.3 fb-1 of data collected by the D0 detector, we observe 15.2 ± 4.4(stat) -0.4+1.9(syst) Ξb- candidates at a mass of 5.774 ± 0.:011(stat) ± 0.015(syst) GeV. The significance of the observed signal …
Measurement Of The Shape Of The Boson Rapidity Distribution For Pp̅ → Z/ Γ* → ℯ+ℯ- + X Events Produced At √S Of 1.96 Tev, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Measurement Of The Shape Of The Boson Rapidity Distribution For Pp̅ → Z/ Γ* → ℯ+ℯ- + X Events Produced At √S Of 1.96 Tev, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Kenneth Bloom Publications
We present a measurement of the shape of the boson rapidity distribution forpp̅ → Z/ γ * → ℯ+ℯ- + X events at a center-of-mass energy of 1.96 TeV. The measurement is made for events with electron-positron mass 71<M ℯℯ < 111 GeV and uses 0.4 fb-1 of data collected at the Fermilab Tevatron collider with the D0 detector. This measurement significantly reduces the uncertainties on the rapidity distribution in the forward region compared with previous measurements. Predictions of next-to-next-to-leading order (NNLO) QCD are found to agree well with the data over the full rapidity range.
Search For Techniparticles In ℯ + Jets Events At D0, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Search For Techniparticles In ℯ + Jets Events At D0, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Kenneth Bloom Publications
Fermilab Tevatron. Technicolor predicts that technipions π T decay dominantly into bb̅, bc̅, or b̅c, depending on their charge. In these events b and c quarks are identified by their secondary decay vertices within jets. Two analysis methods based on topological variables are presented. Since no excess above the standard model prediction was found, the result is presented as an exclusion in the πT vs ρ T mass plane for a given set of model parameters.
Multivariate Searches For Single Top Quark Production With The D0 Detector, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Multivariate Searches For Single Top Quark Production With The D0 Detector, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Kenneth Bloom Publications
We present a search for electroweak production of single top quarks in the s-channel (pp̅→ tb̅ + X) and t-channel (pp̅→tqb̅ + X) modes.We have analyzed 230 pb-1 of data collected with the D0 detector at the Fermilab Tevatron Collider at a center-of-mass energy of √s = 1.96 TeV. No evidence for a single top quark signal is found. We set 95% confidence level upper limits on the production cross sections, based on binned likelihoods formed from a neural network output. The observed (expected) limits are 6.4 pb (4.5 pb) in the …
Measurement Of The Top Quark Mass In The Lepton+Jets Channel Using The Ideogram Method, V. M. Abazov, Kenneth A. Bloom, D0 Collaboration, Gregory R. Snow
Measurement Of The Top Quark Mass In The Lepton+Jets Channel Using The Ideogram Method, V. M. Abazov, Kenneth A. Bloom, D0 Collaboration, Gregory R. Snow
Kenneth Bloom Publications
A measurement of the top quark mass using events with one charged lepton, missing transverse energy, and jets in the final state, collected by the D0 detector from pp̅ collisions at √s= 1.96 TeV at the Fermilab Tevatron collider, is presented. A constrained fit is used to fully reconstruct the kinematics of the events. For every event a top quark mass likelihood is calculated taking into account all possible jet assignments and the probability that an event is signal or background. Lifetime-based identification of b jets is employed to enhance the separation between tt̅ signal and background from other physics …
Evidence For Production Of Single Top Quarks And First Direct Measurement Of |VTb|, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Evidence For Production Of Single Top Quarks And First Direct Measurement Of |VTb|, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Kenneth Bloom Publications
The D0 Collaboration presents first evidence for the production of single top quarks at the Fermilab Tevatron pp̅ collider. Using a 0.9 fb-1 dataset, we apply a multivariate analysis to separate signal from background and measure σ (pp̅ → 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 …
Measurement Of The Charge Asymmetry In Semileptonic BS0 Decays, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collboration
Measurement Of The Charge Asymmetry In Semileptonic BS0 Decays, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collboration
Kenneth Bloom Publications
We have performed the first direct measurement of the time-integrated flavor untagged charge asymmetry in semileptonic Bs0 decays ASLs,unit by comparing the decay rate of Bs0 →μ+Ds- νX, where Ds-→ φ π- and φ → K+K-, with the charge-conjugate B̅s0 decay rate. This sample was selected from 1.3 fb-1 of data collected by the D0 experiment in run II of the Fermilab Tevatron collider. We obtain ASLs,unit= [1.23 ± 0.97(stat) ± 0.17(syst)] …
Lifetime Difference And Cp-Violating Phase In The BS0 System, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Lifetime Difference And Cp-Violating Phase In The BS0 System, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Kenneth Bloom Publications
From an analysis of the decay Bs0 → J/ψφ, we obtain the width difference between the light and heavy mass eigenstates ΔΓ≡(ΓL - ΓH ) = 0.17 ± 0.09(stat) ± 0.02(syst) ps-1 and the CP-violating phase φs= -0.79 ± 0.56(stat) -0.01+0.14 (syst). Under the hypothesis of no CP violation (φs ≡ 0), we obtain 1/ Γ̅= τ̅Bs0 = 1.52 ± 0.08(stat) 0.03+0.01(syst) ps and ΔΓ 0.12-0.10+0.08(stat) ± 0.02(syst) ps-1. The data sample corresponds to an integrated luminosity of about …
Evidence For B0 → Ρ0 Ρ0 Decays And Implications For The Cabibbo-Kobayashi-Maskawa Angle Α, B. Aubert, Kenneth A. Bloom, Babar Collaboration
Evidence For B0 → Ρ0 Ρ0 Decays And Implications For The Cabibbo-Kobayashi-Maskawa Angle Α, B. Aubert, Kenneth A. Bloom, Babar Collaboration
Kenneth Bloom Publications
We search for the decays B0 → ρ0 ρ0, B0 → ρ0f0(980), and B0 → f0(980)f0(980) in a sample of about 384 × 106 Υ (4S)→ BB̅ decays collected with the BABAR detector at the PEP-II asymmetric-energy ℯ+ ℯ- collider at Stanford Linear Accelerator Center. We find evidence for B0 → ρ0 ρ0 with 3.5σ significance and measure the branching fraction Ɓ = 1.07 ± 0:33 ± 0:19) × 10-6 and longitudinal polarization fraction fL …
Experimental Discrimination Between Charge 2ℯ/3 Top Quark And Charge 4ℯ/3 Exotic Quark Production Scenarios, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Experimental Discrimination Between Charge 2ℯ/3 Top Quark And Charge 4ℯ/3 Exotic Quark Production Scenarios, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration
Kenneth Bloom Publications
We present the first experimental discrimination between the 2ℯ/3 and 4ℯ/3 top quark electric charge scenarios, using top quark pairs (tt̅) produced in pp̅ collisions at √s = 1.96 TeV by the Fermilab Tevatron Collider. We use 370 pb-1 of data collected by the D0 experiment and select events with at least one high transverse momentum electron or muon, high transverse energy imbalance, and four or more jets. We discriminate between b- and b̅-quark jets by using the charge and momenta of tracks within the jet cones. The data are consistent with the expected electric …
Us Cms Tier-2 Computing, Kenneth A. Bloom
Us Cms Tier-2 Computing, Kenneth A. Bloom
Kenneth Bloom Publications
The CMS computing model relies heavily on the use of “Tier-2” computing centers. At LHC startup, the typical Tier-2 center in the United States will have 1 MSpecInt2K of CPU resources, 200 TB of disk for data storage, and a WAN connection of 10 Gbit/s. These centers will be the primary sites for the production of large-scale simulation samples and for the hosting of experiment data for user analysis – an interesting mix of experiment-controlled and user-controlled tasks. As a result, there are a wide range of services that must be deployed and commissioned at these centers, which are responsible …
Measurements Of Inclusive W And Z Cross Sections In Pp Collisions At √ S = 1.96tev, A. Abulenci, Kenneth A. Bloom, Cdf Collaboration
Measurements Of Inclusive W And Z Cross Sections In Pp Collisions At √ S = 1.96tev, A. Abulenci, Kenneth A. Bloom, Cdf Collaboration
Kenneth Bloom Publications
We report the first measurements of inclusive W and Z boson cross-sections
times the corresponding leptonic branching ratios for pp collisions at √s = 1.96 TeV based on the decays of the W and Z bosons into electrons and muons. The data were recorded with the CDF II detector at the Fermilab Tevatron and correspond to an integrated luminosity of 72.0 ± 4.3 pb−1. We test e-μ lepton universality in W decays by measuring the ratio of the W → μν to W → eν cross sections and determine a value of 0.991 ±0.004(stat.) ± 0.011(syst.) for …