0000000000060718

AUTHOR

G.s. Muanza

showing 38 related works from this author

Search for the pair production of scalar top quarks in the acoplanar charm jet final state in collisions at

2007

A search for the pair production of scalar top quarks, {bar t}, has been performed in 360 pb{sup -1} of data from p{bar p} collisions at a center-of-mass energy of 1.96 TeV, collected by the D0 detector at the Fermilab Tevatron collider. The {bar t} decay mode considered is {bar t} {yields} c{bar {chi}}{sub 1}{sup 0}, where {bar {chi}}{sub 1}{sup 0} is the lightest supersymmetric particle. The topology analyzed therefore consists of a pair of acoplanar heavy-flavor jets with missing transverse energy. The data show good agreement with the standard model expectation, and a 95% C.L. exclusion domain in the (m{sub {tilde t}}, m{sub {tilde {chi}}{sub 1}{sup 0}}) plane has been determined, exten…

QuarkPhysicsNuclear and High Energy PhysicsParticle physics010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyTevatronSupersymmetry01 natural sciences7. Clean energyLightest Supersymmetric ParticleStandard Modellaw.inventionNuclear physicsPair productionlaw0103 physical sciencesHigh Energy Physics::Experiment010306 general physicsColliderEnergy (signal processing)Physics Letters B
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Measurement of the top quark mass in the dilepton channel

2007

We present a measurement of the top quark mass in the dilepton channel based on approximately 370/pb of data collected by the D0 experiment during Run II of the Fermilab Tevatron collider. We employ two different methods to extract the top quark mass. We show that both methods yield consistent results using ensemble tests of events generated with the D0 Monte Carlo simulation. We combine the results from the two methods to obtain a top quark mass m_t = 178.1 +/- 8.2 GeV. The statistical uncertainty is 6.7 GeV and the systematic uncertainty is 4.8 GeV.

Nuclear and High Energy PhysicsParticle physicsTop quarkMonte Carlo methodTevatronFOS: Physical sciences01 natural sciencesBottom quarkHigh Energy Physics - Experimentlaw.inventionNuclear physicsHigh Energy Physics - Experiment (hep-ex)law0103 physical sciences[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]Physics::Atomic and Molecular ClustersFermilab010306 general physicsColliderNuclear ExperimentPhysics010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyD0 experimentNonlinear Sciences::Exactly Solvable and Integrable SystemsExperimental High Energy PhysicsHigh Energy Physics::ExperimentCommunication channel
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Search for associated Higgs boson production using like charge dilepton events inpp¯collisions ats=1.96  TeV

2011

We present a search for associated Higgs boson production in the process p (p) over bar -> W/ZH -> l(+/-)l'(+/-) + X in ee, e mu, and mu mu final states. The search is based on data collected by the D0 experiment at the Fermilab Tevatron Collider at root s = 1.96 TeV corresponding to 5.3 fb(-1) of integrated luminosity. We require two isolated leptons (electrons or muons) with the same electric charge and additional kinematic requirements. No significant excess above background is observed, and we set 95% C. L. observed (expected) upper limits on ratio of the production cross section to the standard model prediction of 6.4 (7.3) for a Higgs boson mass of 165 GeV and 13.5 (19.8) for a mass o…

PhysicsNuclear and High Energy PhysicsParticle physicsMuon010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyTevatronElementary particleD0 experiment7. Clean energy01 natural sciencesStandard ModelNuclear physics0103 physical sciencesHiggs bosonHigh Energy Physics::Experiment010306 general physicsLeptonBosonPhysical Review D
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Search for scalar leptoquarks in the acoplanar jet topology in pp¯ collisions at s=1.96 TeV

2006

A search for leptoquarks has been performed in 310 pb{sup -1} of data from p{bar p} collisions at a center-of-mass energy of 1.96 TeV, collected by the D0 detector at the Fermilab Tevatron Collider. The topology analyzed consists of acoplanar jets with missing transverse energy. The data show good agreement with standard model expectations, and a lower mass limit of 136 GeV has been set at the 95% C.L. for a scalar leptoquark decaying exclusively into a quark and a neutrino.

QuarkPhysicsNuclear and High Energy PhysicsParticle physics010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyTevatronTopology01 natural sciencesStandard Modellaw.inventionNuclear physicslaw0103 physical sciencesHigh Energy Physics::ExperimentLeptoquarkFermilabNeutrino010306 general physicsColliderLeptonPhysics Letters B
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Search for Sneutrino Production ineμFinal States in5.3  fb−1ofpp¯Collisions ats=1.96  TeV

2010

We report the results of a search for R parity violating (RPV) interactions leading to the production of supersymmetric sneutrinos decaying into emu final states using 5.3 fb^-1 of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider. Having observed no evidence for production of emu resonances, we set direct bounds on the RPV couplings lambda^'_311 and lambda_312 as a function of sneutrino mass.

PhysicsParticle physics010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyTevatronGeneral Physics and AstronomySuperpartnerSupersymmetryD0 experiment01 natural sciences7. Clean energyNuclear physicsR-parity0103 physical sciencesHigh Energy Physics::ExperimentInvariant massFermilab010306 general physicsLeptonPhysical Review Letters
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Measurement of the relative branching ratio ofBs0→J/ψf0(980)toBs0→J/ψϕ

2012

We present a measurement of the relative branching fraction, R-f0/phi, of B-s(0) -> J/psi f(0)(980), with f(0)(980) -> pi(+)pi(-), to the process B-s(0) -> J/psi phi, with phi -> K+K-. The J/psi f(0)(980) final state corresponds to a CP-odd eigenstate of B-s(0) that could be of interest in future studies of CP violation. Using 8 fb(-1) of data recorded with the D0 detector at the Fermilab Tevatron Collider, we find R-f0/phi = 0.275 +/- 0.041(stat) +/- 0.061(syst).

PhysicsNuclear and High Energy PhysicsParticle physicsFuture studies010308 nuclear & particles physicsBranching fraction0103 physical sciencesTevatronCP violationHigh Energy Physics::Experiment010306 general physics01 natural sciencesPhysical Review D
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Measurement oftt¯production in theτ+jetstopology usingpp¯collisions ats=1.96  TeV

2010

We present a measurement of the t (t) over bar production cross section multiplied by the branching ratio to tau lepton decaying semihadronically (tau(h)) plus jets, sigma(p (p) over bar -> t (t) over bar + X) center dot BR(t (t) over bar -> tau(h) + jets), at a center of mass energy root s = 1.96 TeV using 1 fb(-1) of integrated luminosity collected with the D0 detector. Assuming a top quark mass of 170 GeV, we measure sigma(t (t) over bar) center dot BR tau h (+ j) = 0.60(-0.22)(+0.23)(stat)(-0.14)(+0.15)(syst) +/- 0.04(lumi) pb. In addition, we extract the t (t) over bar production cross section using the t (t) over bar -> tau(h) + jets topology, with the result sigma(t (t) over bar) = 6…

PhysicsNuclear and High Energy PhysicsTop quarkParticle physics010308 nuclear & particles physicsBranching fractionHigh Energy Physics::PhenomenologyElementary particleTopology01 natural sciencesNuclear physicsParticle decay0103 physical sciencesHigh Energy Physics::ExperimentCenter of mass010306 general physicsLeptonDimensionless quantityBar (unit)Physical Review D
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Measurement of the differential cross section for the production of an isolated photon with associated jet in pp¯ collisions at s=1.96 TeV

2008

The process ppbar -> photon + jet + X is studied using 1.0 fb^-1 of data collected by the D0 detector at the Fermilab Tevatron ppbar collider at a center-of-mass energy sqrt(s)=1.96 TeV. Photons are reconstructed in the central rapidity region |y_gamma|<1.0 with transverse momenta in the range 3015 GeV. The differential cross section d^3sigma/dPt_gamma dy_gamma dy_jet is measured as a function of Pt_gamma in four regions, differing by the relative orientations of the photon and the jet in rapidity. Ratios between the differential cross sections in each region are also presented. Next-to-leading order QCD predictions using different parameterizations of parton distribution functions and theo…

PhysicsQuantum chromodynamicsNuclear and High Energy PhysicsJet (fluid)Particle physicsPhoton010308 nuclear & particles physicsTevatronParton7. Clean energy01 natural scienceslaw.inventionNuclear physicslaw0103 physical sciencesHigh Energy Physics::ExperimentRapidityFermilab010306 general physicsColliderPhysics Letters B
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Search for scalar top quarks in the acoplanar charm jets and missing transverse energy final state in pp¯ collisions at s=1.96 TeV

2008

We present a search for the pair production of scalar top quarks, $\tilde{t}$, using 995 pb$^{-1}$ of data collected in $p\bar{p}$ collisions with the D0 detector at the Fermilab Tevatron Collider at $\sqrt{s} = 1.96$ TeV. Both scalar top quarks are assumed to decay into a charm quark and a neutralino ($\tilde{\chi}^{0}_{1}$), where $\tilde{\chi}^{0}_{1}$ is the lightest supersymmetric particle. This leads to a final state with two acoplanar charm jets and missing transverse energy. We find the yield of such events to be consistent with the standard model expectation, and exclude sets of $\tilde{t}$ and $\tilde{\chi}^{0}_{1} $ masses at the 95% C.L. that substantially extend the domain excl…

QuarkPhysicsNuclear and High Energy PhysicsParticle physics010308 nuclear & particles physicsHigh Energy Physics::Phenomenology01 natural sciencesLightest Supersymmetric ParticleCharm quarkStandard ModelNuclear physicsPair production0103 physical sciencesNeutralinoHigh Energy Physics::ExperimentCharm (quantum number)010306 general physicsEnergy (signal processing)Physics Letters B
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Search for Higgs bosons decaying to τ+τ− pairs in pp¯ collisions at s=1.96 TeV

2012

Abstract We present a search for the production of neutral Higgs bosons decaying into τ + τ − pairs in p p ¯ collisions at a center-of-mass energy of 1.96 TeV. The data, corresponding to an integrated luminosity of 5.4 fb−1, were collected by the D0 experiment at the Fermilab Tevatron Collider. We set upper limits at the 95% C.L. on the product of production cross section and branching ratio for a scalar resonance decaying into τ + τ − pairs, and we interpret these limits as limits on the production of Higgs bosons in the minimal supersymmetric standard model (MSSM) and as constraints in the MSSM parameter space.

PhysicsNuclear and High Energy PhysicsParticle physics010308 nuclear & particles physicsBranching fractionHigh Energy Physics::PhenomenologyScalar (mathematics)Tevatron7. Clean energy01 natural scienceslaw.inventionStandard ModelNuclear physicslaw0103 physical sciencesHiggs bosonHigh Energy Physics::Experiment010306 general physicsColliderMinimal Supersymmetric Standard ModelBosonPhysics Letters B
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Search for the Standard Model Higgs Boson in theH→WW→lνq′q¯Decay Channel

2011

We present a search for the standard model Higgs boson (H) in ppbar collisions at sqrt{s}=1.96 TeV in events containing a charged lepton (ell), missing transverse energy, and at least two jets, using 5.4 fb^-1 of integrated luminosity recorded with the D0 detector at the Fermilab Tevatron Collider. This analysis is sensitive primarily to Higgs bosons produced through the fusion of two gluons or two electroweak bosons, with subsequent decay H->WW->ell+nu+q'qbar, where ell is an electron or muon. The search is also sensitive to contributions from other production channels, such as WH->ell+nu+bbbar In the absence of signal, we set limits at the 95% C.L. on the cross section for H production si…

PhysicsParticle physicsMuon010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyElectroweak interactionTevatronGeneral Physics and AstronomyElementary particle7. Clean energy01 natural sciencesStandard ModelNuclear physics0103 physical sciencesHiggs bosonHigh Energy Physics::Experiment010306 general physicsBosonLeptonPhysical Review Letters
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Measurement of the ratios of the Z/γ∗+⩾n jet production cross sections to the total inclusive Z/γ∗ cross section in pp¯ collisions at s=1.96 TeV

2008

We present a study of events with Z bosons and jets produced at the Fermilab Tevatron Collider in ppbar collisions at a center of mass energy of 1.96 TeV. The data sample consists of nearly 14,000 Z/G* -> e+e- candidates corresponding to the integrated luminosity of 340 pb-1 collected using the D0 detector. Ratios of the Z/G* + >= n jet cross sections to the total inclusive Z/G* cross section have been measured for n = 1 to 4 jet events. Our measurements are found to be in good agreement with a next-to-leading order QCD calculation and with a tree-level QCD prediction with parton shower simulation and hadronization.

Quantum chromodynamicsPhysicsNuclear and High Energy PhysicsParticle physicsLuminosity (scattering theory)010308 nuclear & particles physicsAstrophysics::High Energy Astrophysical PhenomenaHigh Energy Physics::PhenomenologyTevatronJet (particle physics)01 natural sciences7. Clean energyHadronizationNuclear physics0103 physical sciencesHigh Energy Physics::ExperimentCenter of mass010306 general physicsParton showerBosonPhysics Letters B
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Search for the lightest scalar top quark in events with two leptons in pp¯ collisions at s=1.96 TeV

2009

Abstract We report results of a search for the pair production of the lightest supersymmetric partner of the top quark, t ˜ 1 , using a data set corresponding to an integrated luminosity of 1 fb −1 collected by the DO detector at a p p ¯ center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider. Both scalar top quarks are assumed to decay into a b quark, a charged lepton and a scalar neutrino. The search is performed in the electron plus muon and dielectron final states. The signal topology consists of two isolated leptons, missing transverse energy, and jets. We find no evidence for this process and exclude regions of parameter space in the framework of the minimal supersymmetric…

QuarkPhysicsNuclear and High Energy PhysicsParticle physicsTop quark010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyTevatronElementary particle7. Clean energy01 natural sciencesBottom quarkNuclear physicsPair production0103 physical sciencesHigh Energy Physics::ExperimentFermilabNeutrino010306 general physicsLeptonMinimal Supersymmetric Standard ModelPhysics Letters B
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Search for first generation leptoquark pair production in the electron + missing energy + jets final state

2011

We present a search for the pair production of first generation scalar leptoquarks (LQ) in data corresponding to an integrated luminosity of 5.4 fb$^{-1}$ collected with the D0 detector at the Fermilab Tevatron Collider in ppbar collisions at $\sqrt{s}=1.96$ TeV. In the channel $LQ \bar{LQ} \rightarrow e\nu_e qq'$, where q, q' are u or d quarks, no significant excess of data over background is observed, and we set a 95% C.L. lower limit of 326 GeV on the leptoquark mass, assuming equal probabilities of leptoquark decays to eq and $\nu_e q'$.

PhysicsNuclear and High Energy PhysicsParticle physicsMissing energy010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyTevatronFOS: Physical sciencesElementary particle7. Clean energy01 natural scienceslaw.inventionHigh Energy Physics - ExperimentNuclear physicsHigh Energy Physics - Experiment (hep-ex)Particle decayPair productionlaw0103 physical sciences[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]LeptoquarkHigh Energy Physics::Experiment010306 general physicsColliderLepton
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Measurement of the tt¯ production cross section and top quark mass extraction using dilepton events in pp¯ collisions

2009

We present a measurement of the top quark pair production cross section in p (p) over bar collisions at root s = 1.96 TeV using approximately 1 fb(-1) collected with the DO detector. We consider decay channels containing two high p(T) charged leptons where one lepton is identified as an electron or a muon while the other lepton can be an electron, a muon or a hadronically decaying tau lepton. For a mass of the top quark of 170 GeV, the measured cross section is 7.5(-1.0)(+1.0)(stat)(-0.6)(+0.7)(syst)(-0.5)(+0.6)(lumi) pb. Using l tau events only, we measure: sigma(t (t) over bar) x B(t (t) over bar -> l tau b (b) over bar) = 0.13(-0.08)(+0.09)(stat)(-0.06)(+0.06)(syst)(-0.02)(+0.02)(lumi) p…

Quantum chromodynamicsPhysicsNuclear and High Energy PhysicsTop quarkParticle physicsMuon010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyElectron01 natural sciences7. Clean energyNuclear physicsCross section (physics)Pair production0103 physical sciencesHigh Energy Physics::Experiment010306 general physicsLeptonBar (unit)Physics Letters B
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Erratum to: “Search for particles decaying into a Z boson and a photon in pp¯ collisions at s=1.96 TeV” [Phys. Lett. B 641 (2006) 415]

2009

Search for particles decaying into a Z boson and a photon in collisions p (p)over-bar at root s = 1.96 TeV (vol 641, pg 415, 2006)

PhysicsNuclear and High Energy PhysicsParticle physicsPhoton010308 nuclear & particles physicsHigh Energy Physics::Phenomenology0103 physical sciencesHigh Energy Physics::Experiment010303 astronomy & astrophysics01 natural sciencesPhysics Letters B
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Search for Higgs bosons of the minimal supersymmetric standard model in pp¯ collisions at s=1.96 TeV

2012

We report results from searches for neutral Higgs bosons produced in p-pbar collisions recorded by the Dzero experiment at the Fermilab Tevatron Collider. We study the production of inclusive neutral Higgs boson in the tautau final state and in association with a b quark in the btautau and bbb final states. These results are combined to improve the sensitivity to the production of neutral Higgs bosons in the context of the minimal supersymmetric standard model (MSSM). The data are found to be consistent with expectation from background processes. Upper limits on MSSM Higgs boson production are set for Higgs boson masses ranging from 90 to 300 GeV. We exclude tanBeta>20-30 for Higgs boson ma…

Condensed Matter::Quantum GasesPhysicsNuclear and High Energy PhysicsParticle physics010308 nuclear & particles physicsHigh Energy Physics::LatticeHigh Energy Physics::PhenomenologyElementary particleTechnicolor01 natural sciences7. Clean energyBottom quarkStandard ModelNuclear physicssymbols.namesake0103 physical sciencessymbolsHiggs bosonHigh Energy Physics::Experiment010306 general physicsHiggs mechanismMinimal Supersymmetric Standard ModelBosonPhysics Letters B
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Measurement of the isolated photon cross section in pp¯ collisions at s=1.96 TeV

2006

The cross section for the inclusive production of isolated photons has been measured in p anti-p collisions at sqrt{s}=1.96 TeV with the D0 detector at the Fermilab Tevatron Collider. The photons span transverse momenta 23 to 300 GeV and have pseudorapidity |eta|<0.9. The cross section is compared with the results from two next-to-leading order perturbative QCD calculations. The theoretical predictions agree with the measurement within uncertainties.

PhysicsNuclear and High Energy PhysicsParticle physicsPhoton010308 nuclear & particles physicsTevatronPerturbative QCD7. Clean energy01 natural sciencesNuclear physicsTransverse planePseudorapidity0103 physical sciencesHigh Energy Physics::ExperimentFermilabNuclear Experiment010306 general physicsPhysics Letters B
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Erratum to: “Measurement of the isolated photon cross section in pp¯ collisions at s=1.96 TeV” [Phys. Lett. B 639 (2006) 151]

2008

Measurement of the isolated photon cross section in p(p)over-bar collisions at root s = 1.96 TeV (vol 639, pg 151, 2006)

Nuclear physicsPhysicsNuclear and High Energy PhysicsCross section (physics)Photon010308 nuclear & particles physics0103 physical sciences010306 general physics01 natural sciencesPhysics Letters B
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Search for a Higgs boson produced in association with a Z boson

2007

We describe a search for the Standard Model Higgs boson with a mass of 105 GeV/c(2) to 145 GeV/c(2) in data corresponding to an integrated luminosity of approximately 450 pb(-1) collected with the D phi detector at the Fermilab Tevatron p (p) over bar collider at a center-of-mass energy of 1.96 TeV. The Higgs boson is required to be produced in association with a Z boson, and the Z boson is required to decay to either electrons or muons with the Higgs boson decaying to a b (b) over bar pair. The data are well described by the expected background, leading to 95% confidence level cross section upper limits sigma (p (p) over bar -> ZH) x B(H -> b (b) over bar) in the range of 3.1 pb to 4.4 pb.

PhysicsNuclear and High Energy PhysicsParticle physicsMuonLuminosity (scattering theory)010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyTevatron7. Clean energy01 natural scienceslaw.inventionStandard ModellawExperimental High Energy Physics0103 physical sciencesHiggs bosonHigh Energy Physics::ExperimentFermilab010306 general physicsColliderBosonPhysics Letters B
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Zγ production and limits on anomalous ZZγ and Zγγ couplings in pp¯ collisions at s=1.96 TeV

2007

We present a study of eey and mu mu gamma events using 1109 (1009) pb-(1) of data in the electron (muon) channel, respectively. These data were collected with the DO detector at the Fermilab Tevatron pp collider at Is = 1.96 TeV. Having observed 453 (515) candidates in the eey (jtAy) final state, we measure the Z gamma production cross section for a photon with transverse energy ET > 7 GeV, separation between the photon and leptons Delta Rey > 0.7, and invariant mass of the di-lepton pair Mee > 30 GeV/(2)(c), to be 4.96 0.30(stat. + syst.) zE 0.30(lumi.) pb, in agreement with the Standard Model prediction of 4.74 0.22 pb. This is the most precise Zy cross section measurement at a hadron col…

PhysicsNuclear and High Energy PhysicsGauge bosonParticle physicsMuonLarge Hadron Collider010308 nuclear & particles physicsTevatron01 natural sciences7. Clean energylaw.inventionStandard ModelNuclear physicslaw0103 physical sciencesHigh Energy Physics::ExperimentFermilab010306 general physicsColliderLeptonPhysics Letters B
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Search forCPviolation inBs0→μ+Ds−Xdecays inpp¯collisions ats=1.96  TeV

2010

We have performed a search for CP violation in a sample of B-s(0) -> mu+Ds-X decays corresponding to 5 fb(-1) of proton-antiproton collisions collected by the D0 detector in Run II at the Fermilab Tevatron Collider. New physics in B-s(0) mixing could contribute a significant CP violating weak phase, which would be observed as a difference in the decay-time distribution for B-s(0) -> (B) over bar (0)(s) oscillated states versus that for (B) over bar (0)(s) -> B-s(0). A fit to the decay-time distributions of the B-s(0)/(B) over bar (0)(s) candidates yields the flavor-specific asymmetry as a(fs)(s) = [-1.7 +/- 9.1(stat)(-1.5)(+1.4)(syst) x 10(-3), which excludes CP violation due to new physics…

PhysicsNuclear and High Energy PhysicsParticle physicsMuonMeson010308 nuclear & particles physicsPhysics beyond the Standard ModelHadronTevatron01 natural sciencesNuclear physicsParticle decay0103 physical sciencesCP violationHigh Energy Physics::Experiment010306 general physicsLeptonPhysical Review D
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Model independent search for new phenomena inpp¯collisions ats=1.96  TeV

2012

We describe a model independent search for physics beyond the standard model in lepton final states. We examine 117 final states using 1.1 fb$^{-1}$ of $p \bar{p}$ collisions data at $\sqrt{s} = 1.96$ TeV collected with the D0 detector. We conclude that all observed discrepancies between data and model can be attributed to uncertainties in the standard model background modeling, and hence we do not see any evidence for physics beyond the standard model.

PhysicsNuclear and High Energy PhysicsParticle physics010308 nuclear & particles physicsBar (music)Physics beyond the Standard ModelDetector01 natural sciencesStandard ModelNuclear physics0103 physical sciencesHigh Energy Physics::Experiment010306 general physicsLeptonPhysical Review D
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Search for R-parity violating supersymmetry via the LLE¯ couplings λ121, λ122 or λ133 in pp¯ collisions at s=1.96 TeV

2006

A search for gaugino pair production with a trilepton signature in the framework of R-parity violating supersymmetry via the couplings lambda_121, lambda_122, or lambda_133 is presented. The data, corresponding to an integrated luminosity of L~360/pb, were collected from April 2002 to August 2004 with the D0 detector at the Fermilab Tevatron Collider, at a center-of-mass energy of sqrt(s)=1.96 TeV. This analysis considers final states with three charged leptons with the flavor combinations eel, mumul, and eetau (l=e or mu). No evidence for supersymmetry is found and limits at the 95% confidence level are set on the gaugino pair production cross section and lower bounds on the masses of the …

PhysicsNuclear and High Energy PhysicsParticle physics010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyGauginoTevatronSupersymmetryLambda7. Clean energy01 natural sciencesNuclear physicsCharginoPair productionR-parity0103 physical sciencesNeutralinoHigh Energy Physics::Experiment010306 general physicsPhysics Letters B
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Search for charged massive long-lived particles

2012

We report on a search for charged massive long-lived particles (CMLLPs), based on 5.2 fb$^{-1}$ of integrated luminosity collected with the D0 detector at the Fermilab Tevatron $p\bar{p}$ collider. We search for events in which one or more particles are reconstructed as muons but have speed and ionization energy loss $(dE/dx)$ inconsistent with muons produced in beam collisions. CMLLPs are predicted in several theories of physics beyond the standard model. We exclude pair-produced long-lived gaugino-like charginos below 267 GeV and higgsino-like charginos below 217 GeV at 95% C.L., as well as long-lived scalar top quarks with mass below 285 GeV.

Particle physicsPhysics beyond the Standard ModelTevatronFOS: Physical sciencesGeneral Physics and Astronomy01 natural sciencesHigh Energy Physics - ExperimentStandard Modellaw.inventionNuclear physicsHigh Energy Physics - Experiment (hep-ex)law0103 physical sciences[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]Fermilab010306 general physicsColliderPhysicsMuonLuminosity (scattering theory)010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyParticle acceleratorExperimental High Energy PhysicsPhysics::Accelerator PhysicsHigh Energy Physics::Experiment
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Measurement of the ratio of the pp¯→W+c-jet cross section to the inclusive pp¯→W+jets cross section

2008

We present a measurement of the fraction of inclusive W +jets events produced with net charm quantum number 11, denoted W + c-jet, in p collisions at root s = 1.96 TeV using approximately 1 fb(-1) of data collected by the DO detector at the Fermilab Tevatron Collider. We identify the W +jets events via the leptonic W boson decays. Candidate W + c-jet events are selected by requiring a jet containing a muon in association with a reconstructed W boson and exploiting the charge correlation between this muon and W boson decay lepton to perform a nearly model-independent background subtraction. We measure the fraction of W + c-jet events in the inclusive W +jets sample for jet PT > 20 GeV and ps…

PhysicsNuclear and High Energy PhysicsJet (fluid)Particle physicsMuon010308 nuclear & particles physicsAstrophysics::High Energy Astrophysical PhenomenaTevatronCharge (physics)01 natural sciences7. Clean energylaw.inventionNuclear physicslawPseudorapidity0103 physical sciencesHigh Energy Physics::ExperimentFermilabNuclear Experiment010306 general physicsColliderLeptonPhysics Letters B
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Measurement ofγ+b+Xandγ+c+XProduction Cross Sections inpp¯Collisions ats=1.96  TeV

2009

First measurements of the differential cross sections for the inclusive production of a photon in association with a heavy quark (c, b) jet are presented, covering photon transverse momenta 30-150 GeV, photon rapidities | y_gamma| 15 GeV. The results are based on an integrated luminosity of 1 fb^-1 in ppbar collisions at sqrt(s)=1.96 TeV recorded with the D0 detector at the Fermilab Tevatron Collider. The results are compared with next-to-leading order perturbative QCD predictions.

Quantum chromodynamicsQuarkPhysicsParticle physicsLuminosity (scattering theory)010308 nuclear & particles physicsAstrophysics::High Energy Astrophysical PhenomenaHigh Energy Physics::PhenomenologyTevatronGeneral Physics and AstronomyPerturbative QCDJet (particle physics)7. Clean energy01 natural scienceslaw.inventionNuclear physicslaw0103 physical sciencesHigh Energy Physics::ExperimentFermilabNuclear Experiment010306 general physicsColliderPhysical Review Letters
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Search for supersymmetry in di-photon final states at s=1.96 TeV

2008

We report results of a search for supersymmetry (SUSY) with gauge-mediated symmetry breaking in di-photon events collected by the DO experiment at the Fermilab Tevatron Collider in 2002-2006. In 1.1 fb(-1) of data, we find no significant excess beyond the background expected from the standard model and set the most stringent lower limits to date for a standard benchmark model on the lightest neutralino and chargino masses of 125 GeV and 229 GeV, respectively, at 95% confidence.

PhysicsNuclear and High Energy PhysicsParticle physics010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyTevatronSupersymmetry01 natural sciencesStandard ModelNuclear physicsChargino0103 physical sciencesNeutralinoHigh Energy Physics::ExperimentGravitinoFermilabSymmetry breaking010306 general physicsPhysics Letters B
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Precise Study of theZ/γ*Boson Transverse Momentum Distribution inpp¯Collisions Using a Novel Technique

2011

Using 7.3 pb-1 of ppbar collisions collected by the D0 detector at the Fermilab Tevatron, we measure the distribution of the variable \phistar, which probes the same physical effects as the Z/gamma* boson transverse momentum, but is less susceptible to the effects of experimental resolution and efficiency. A QCD prediction is found to describe the general features of the \phistar distribution, but is unable to describe its detailed shape or dependence on boson rapidity. A prediction that includes a broadening of transverse momentum for small values of the parton momentum fraction is strongly disfavored.

Quantum chromodynamicsPhysicsParticle physics010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyTevatronGeneral Physics and AstronomyParton01 natural sciencesMeasure (mathematics)MomentumNuclear physics0103 physical sciencesHigh Energy Physics::ExperimentRapidityFermilabNuclear Experiment010306 general physicsBosonPhysical Review Letters
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Search for particles decaying into a Z boson and a photon in pp¯ collisions at s=1.96 TeV

2006

Abstract We present the results of a search for a new particle X produced in p p ¯ collisions at s = 1.96 TeV and subsequently decaying to Zγ. The search uses 0.3 fb−1 of data collected with the DO detector at the Fermilab Tevatron Collider. We set limits on the production cross section times the branching fraction σ ( p p ¯ → X ) × B ( X → Z γ ) that range from 0.4 to 3.5 pb at the 95% C.L. for X with invariant masses between 100 and 1000 GeV / c 2 , over a wide range of X decay widths.

PhysicsNuclear and High Energy PhysicsRange (particle radiation)Particle physicsPhoton010308 nuclear & particles physicsBranching fractionTevatron7. Clean energy01 natural scienceslaw.inventionCross section (physics)law0103 physical sciencesHigh Energy Physics::ExperimentFermilabInvariant (mathematics)010306 general physicsColliderPhysics Letters B
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A combined search for the standard model Higgs boson at s=1.96 TeV

2008

AbstractWe present new results of the search for WH→ℓνbb¯ production in pp¯ collisions at a center-of-mass energy of s=1.96 TeV, based on a dataset with integrated luminosity of 0.44 fb−1. We combine these new results with previously published searches by the D0 collaboration, for WH and ZH production analyzed in the E̸Tbb¯ final state, for ZH (→ℓ+ℓ−bb¯) production, for WH (→WWW) production, and for H (→WW) direct production. No signal-like excess is observed either in the WH analysis or in the combination of all D0 Higgs boson analyses. We set 95% C.L. (expected) upper limits on σ(pp¯→WH)×B(H→bb¯) ranging from 1.6 (2.2) pb to 1.9 (3.3) pb for Higgs boson masses between 105 and 145 GeV, to …

PhysicsNuclear and High Energy PhysicsParticle physicsLuminosity (scattering theory)010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyState (functional analysis)7. Clean energy01 natural sciencesStandard ModelNuclear physicsDirect production0103 physical sciencesHiggs bosonHigh Energy Physics::ExperimentCenter of massNeutrino010306 general physicsLeptonPhysics Letters B
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Search for tt¯ resonances in the lepton plus jets final state in pp¯ collisions at s=1.96TeV

2008

We present a search for a narrow-width heavy resonance decaying into top quark pairs X->ttbar in ppbar collisions at sqrt{s}=1.96TeV using approximately 0.9fb^-1 of data collected with the D0 detector at the Fermilab Tevatron Collider. This analysis considers ttbar candidate events in the lepton plus jets channel with at least one identified b jet and uses the ttbar invariant mass distribution to search for evidence of resonant production. We find no evidence for a narrow resonance X decaying to ttbar. Therefore, we set upper limits on sigma*B(X->ttbar) for different hypothesized resonance masses using a Bayesian approach. For a Topcolor-assisted technicolor model, the existence of a leptop…

PhysicsNuclear and High Energy PhysicsParticle physicsTop quark010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyHadronTopcolorTevatronTechnicolor7. Clean energy01 natural sciencesNuclear physics0103 physical sciencesHigh Energy Physics::ExperimentInvariant mass010306 general physicsLeptonBosonPhysics Letters B
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Search for a scalar or vector particle decaying into Zγ in pp¯ collisions at s=1.96 TeV

2009

We present a search for a narrow scalar or vector resonance decaying into Z gamma with a subsequent Z boson decay into a pair of electrons or moons. The data for this search were collected with the D circle divide detecror at the Fermilab Tevatron p (p) over bar collider at a center of mass energy root s = 1.96 TeV. Using 1.1 (1.0) fb(-1) of data, we observe 49 (50) candidate events in the electron (muon) channel, in good agreement with the standard model prediction. From the combination of both channels, we derive 95% C.L. upper limits on the cross section times branching fraction (sigma x B) into Z gamma. These limits range from 0.19 (0.20) pb for a scalar (vector) resonance mass of 600 G…

PhysicsNuclear and High Energy PhysicsParticle physicsPhotonMuon010308 nuclear & particles physicsBranching fractionScalar (mathematics)TevatronElectron01 natural sciencesNuclear physics0103 physical sciencesHigh Energy Physics::ExperimentFermilab010306 general physicsBosonPhysics Letters B
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Search for single production of scalar leptoquarks in pp¯ collisions decaying into muons and quarks with the D0 detector

2007

We report on a search for second generation leptoquarks LQ_2 which decay into a muon plus quark in p\bar{p} collisions at a center-of-mass energy of sqrt{s} = 1.96 TeV in the D0 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 beta into a quark and a muon was determined for second generation scalar leptoquarks as a function of the leptoquark mass. This result has been combined with a previously published D0 search for leptoquark pair production to obtain leptoquark mass limits as a function of the leptoquark-muon-quark cou…

PhysicsQuarkNuclear and High Energy PhysicsParticle physicsMuon010308 nuclear & particles physicsBranching fractionHigh Energy Physics::PhenomenologyScalar (mathematics)Lambda01 natural sciencesUpper and lower boundsNuclear physicsPair production0103 physical sciencesHigh Energy Physics::ExperimentLeptoquark010306 general physicsPhysics Letters B
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Search for a heavy neutral gauge boson in the dielectron channel with 5.4 fb−1 of pp¯ collisions at s=1.96 TeV

2011

We report the results of a search for a heavy neutral gauge boson Z' decaying into the dielectron final state using data corresponding to an integrated luminosity of 5.4 fb(-1) collected by the D0 experiment at the Fermilab Tevatron Collider. No significant excess above the standard model prediction is observed in the dielectron invariant-mass spectrum. We set 95 sigma(p (p) over bar -> Z') x BR(Z' -> ee) depending on the dielectron invariant mass. These cross section limits are used to determine lower mass limits for bosons in a variety of models. For the sequential standard model boson a lower mass limit of 1023 GeV is obtained.

PhysicsNuclear and High Energy PhysicsParticle physicsGauge boson010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyTevatronD0 experiment01 natural scienceslaw.inventionStandard ModelNuclear physicslaw0103 physical sciencesHigh Energy Physics::ExperimentInvariant massFermilabNuclear Experiment010306 general physicsColliderBosonPhysics Letters B
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Measurement ofsin2θeffℓandZ-light quark couplings using the forward-backward charge asymmetry inpp¯→Z/γ*→e+e−events withL=5.0  fb−1ats=1.96  TeV

2011

We measure the mass dependence of the forward-backward charge asymmetry in 157,553 $p\bar{p} \rightarrow Z/\gamma^{*} \rightarrow e^+e^-$ interactions, corresponding to 5.0 fb$^{-1}$ of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider at $\sqrt{s}=1.96$ TeV. The effective weak mixing angle ($\sin^2\theta_{eff}^{lept}$) from this process involving predominantly the first generation of quarks is extracted as $\sin^2\theta_{eff}^{lept} = 0.2309 \pm 0.0008 ({stat.}) \pm 0.0006 ({syst.})$. We also present the most precise direct measurement of the vector and axial-vector couplings of $u$ and $d$ quarks to the $Z$ boson.

QuarkPhysicsNuclear and High Energy PhysicsParticle physicsLuminosity (scattering theory)010308 nuclear & particles physicsmedia_common.quotation_subjectHigh Energy Physics::PhenomenologyTevatronDrell–Yan processCharge (physics)Weinberg angle7. Clean energy01 natural sciencesAsymmetryNuclear physics0103 physical sciencesHigh Energy Physics::Experiment010306 general physicsmedia_commonBosonPhysical Review D
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Search for W′→tb resonances with left- and right-handed couplings to fermions

2011

We present a search for the production of a heavy gauge boson, W', that decays to third-generation quarks, by the D0 Collaboration in ppbar collisions at sqrt(s)= 1.96 TeV. We set 95% confidence level upper limits on the production cross section times branching fraction. For the first time, we set limits for arbitrary combinations of left- and right-handed couplings of the W' boson to fermions. For couplings with the same strength as the standard model W boson, we set the following limits for M(W') > m(nu_R): M(W')>863 GeV for purely left-handed couplings, M(W')>885 GeV for purely right-handed couplings, and M(W')>916 GeV if both left- and right-handed couplings are present. The limit for r…

PhysicsQuarkNuclear and High Energy PhysicsTop quarkParticle physicsGauge boson010308 nuclear & particles physicsBranching fractionHigh Energy Physics::PhenomenologyFermion01 natural sciences7. Clean energyBottom quarkStandard ModelNuclear physics0103 physical sciencesHigh Energy Physics::ExperimentNuclear Experiment010306 general physicsBosonPhysics Letters B
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Search for W′ boson production in the W′→tb¯ decay channel

2006

We present a search for the production of a new heavy gauge boson W' that decays to a top quark and a bottom quark. We have analyzed 230 pb(-1) of data collected with the DO detector at the Fermilab Tevatron collider at a center-of-mass energy of 1.96 TeV. No significant excess of events above the standard model expectation is found in any region of the final state invariant mass distribution. We set upper limits on the production cross section of W' bosons times branching ratio to top quarks at the 95% confidence level for several different W, boson masses. We exclude masses between 200 and 610 GeV for a W' boson with standard-model-like couplings, between 200 and 630 GeV for a W, boson wi…

QuarkPhysicsNuclear and High Energy PhysicsGauge bosonTop quarkParticle physics010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyScalar boson7. Clean energy01 natural sciencesBottom quarkStandard ModelNuclear physicsW and Z bosons0103 physical sciencesHigh Energy Physics::Experiment010306 general physicsBosonPhysics Letters B
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