Now showing items 200-219 of 428

    • A New Method to Distinguish Hadronically Decaying Boosted Z Bosons from W Bosons Using the ATLAS Detector 

      Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Aben, R.; Abolins, M.; AbouZeid, O. S.; Izen, Joseph M.; Leyton, Michael; Meirose, Bernhard; Namasivayam, Harisankar; Reeves, Kendall; ATLAS Collaboration (Springer LLC, 2016-04-28)
      The distribution of particles inside hadronic jets produced in the decay of boosted W and Z bosons can be used to discriminate such jets from the continuum background. Given that a jet has been identified as likely resulting ...
    • Observation and Measurement of Higgs Boson Decays to WW* with the ATLAS Detector 

      Aad, G.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdinov, O.; Aben, R.; Abi, B.; Izen, Joseph M.; Leyton, Michael; Meirose, Bernhard; Namasivayam, Harisankar; Reeves, Kendall; ATLAS Collaboration (Amer Physical Soc, 2015-07-16)
      We report the observation of Higgs boson decays to WW* based on an excess over background of 6.1 standard deviations in the dilepton final state, where the Standard Model expectation is 5.8 standard deviations. Evidence ...
    • Observation and Measurements of the Production of Prompt and Non-Prompt J/ψ Mesons in Association with a Z Boson in pp Collisions at √s̅ = 8 TeV with the ATLAS Detector 

      Aad, G.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdinov, O.; Aben, R.; Abi, B.; Izen, Joseph M.; Leyton, Michael; Meirose, Bernhard; Namasivayam, Harisankar; Reeves, Kendall; ATLAS Collaboration (Springer, 2015-05-27)
      The production of a Z boson in association with a J/ψ meson in proton-proton collisions probes the production mechanisms of quarkonium and heavy flavour in association with vector bosons, and allows studies of multiple ...
    • Observation and Study of the Baryonic B-Meson Decays B→D^{(*)}pp̅ (π)(π) 

      Del Amo Sanchez, P.; Lees, J. P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration (American Physical Society, 2012-05-30)
      We present results for B-meson decay modes involving a charm meson, protons, and pions using 455×10⁶ BB̄ pairs recorded by the BaBar detector at the SLAC PEP-II asymmetric-energy e⁺e⁻ collider. The branching fractions ...
    • Observation of an Excited B_c ^{±} Meson State with the ATLAS Detector 

      Aad, G.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdinov, O.; Aben, R.; Abi, B.; Izen, Joseph M.; Leyton, Michael; Lou, Xinchou; Namasivayam, Harisankar; Reeves, Kendall; ATLAS Collaboration (American Physical Society, 2014-11-21)
      A search for excited states of theB(±)(c) meson is performed using 4.9 fb⁻¹ of 7 TeV and 19.2 fb⁻¹ of 8 TeV pp collision data collected by the ATLAS experiment at the LHC. A new state is observed through its hadronic ...
    • Observation of B̅ → D* π⁺π⁻ℓ⁻ν̅ Decays in e⁺e⁻ Collisions at the ϒ(4s) Resonance 

      Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration (Amer Physical Soc, 2016-01-26)
      We report on measurements of the decays of B̅ mesons into the semileptonic final states B̅ → D^{(*)} π⁺π⁻ℓ⁻ν̅, where D^{(*())} represents a D or D* meson and ℓ⁻ is an electron or a muon. These measurements are based on 471 ...
    • Observation of Electroweak W^{±} Z Boson Pair Production in Association with Two Jets in pp Collisions at√s=13 TeV with the ATLAS Detector 

      Aaboud, M.; Aad, G.; Abbott, B.; Abdinov, O.; Abeloos, B.; Abhayasinghe, D. K.; Abidi, S. H.; Izen, Joseph M.; Meirose, Bernhard; Reeves, Kendall; ATLAS Collaboration (Elsevier B.V., 2019-05-13)
      An observation of electroweak W^{±} Z production in association with two jets in proton–proton collisions is presented. The data collected by the ATLAS detector at the Large Hadron Collider in 2015 and 2016 at a centre-of-mass ...
    • Observation of Spin Correlation in tt̄ Events from pp Collisions at √s = 7 TeV Using the ATLAS Detector 

      Aad, G.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdelalim, A. A.; Abdesselam, A.; Abdinov, O.; Ahsan, Mahsana; Izen, Joseph M.; Lou, Xinchou; Reeves, Kendall; Wong, Wei-Cheng; ATLAS Collaboration (American Physical Society, 2012-05-24)
      A measurement of spin correlation in tt̅ production is reported using data collected with the ATLAS detector at the LHC, corresponding to an integrated luminosity of 2.1 fb⁻¹. Candidate events are selected in the dilepton ...
    • Observation of Time-Reversal Violation in the B⁰ Meson System 

      Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration (American Physical Society, 2012-11-19)
      Although CP violation in the B meson system has been well established by the B factories, there has been no direct observation of time-reversal violation. The decays of entangled neutral B mesons into definite flavor states ...
    • Observation of Top-Quark Pair Production in Association with a Photon and Measurement of the tt̅γ Production Cross Section in pp Collisions at √s=7 TeV Using the ATLAS Detector 

      Aad, G.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdinov, O.; Aben, R.; Abi, B.; Izen, Joseph M.; Leyton, Michael; Lou, Xinchou; Namasivayam, Harisankar; Reeves, Kendall; ATLAS Collaboration (Amer Physical Soc, 2015-04-01)
      A search is performed for top-quark pairs tt̅ produced together with a photon (γ) with transverse energy greater than 20 GeV using a sample of tt̅ candidate events in final states with jets, missing transverse momentum, ...
    • Performance of Algorithms that Reconstruct Missing Transverse Momentum in √s̅ = 8 TeV Proton–Proton Collisions in the ATLAS Detector 

      Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Abeloos, B.; Aben, R.; Abolins, M.; Izen, Joseph M.; Meirose, Bernhard; Namasivayam, Harisankar; Leyton, Michael; Reeves, Kendall; ATLAS Collaboration (Springer New York LLC, 2018-05-15)
      Direct searches for lepton flavour violation in decays of the Higgs and Z bosons with the ATLAS detector at the LHC are presented. The following three decays are considered: H → eτ, H →μτ, and Z → μτ. The searches are based ...
    • Performance of the ATLAS Muon Trigger in pp Collisions at √s̅ = 8 TeV 

      Aad, G.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdinov, O.; Aben, R.; Abi, B.; Izen, Joseph M.; Leyton, Michael; Lou, Xinchou; Namasivayam, Harisankar; Reeves, Kendall; ATLAS Collaboration (EDP Sciences, 2015-03-13)
      The performance of the ATLAS muon trigger system is evaluated with proton-proton collision data collected in 2012 at the Large Hadron Collider at a centre-of-mass energy of 8 TeV. It is primarily evaluated using events ...
    • Performance of the ATLAS Track Reconstruction Algorithms in Dense Environments in LHC Run 2 

      Aaboud, M.; Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Abeloos, B.; Abidi, S. H.; AbouZeid, O. S.; Izen, Joseph M.; Meirose, Bernhard; Reeves, Kendall; Leyton, Michael; ATLAS Collaboration (Springer New York LLC, 2018-05-15)
      Measurements of the electroweak production of a W boson in association with two jets at high dijet invariant mass are performed using √s̅ = 7 and 8 TeV proton–proton collision data produced by the Large Hadron Collider, ...
    • Performance of the ATLAS Trigger System in 2015 

      Aaboud, M.; Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Abeloos, B.; Aben, R.; Izen, Joseph M.; Leyton, Michael; Meirose, Bernhard; Reeves, Kendall (Springer New York LLC, 2018-05-15)
      This article presents measurements of tt̅ differential cross-sections in a fiducial phase-space region, using an integrated luminosity of 3.2 fb⁻¹ of proton–proton data at a centre-of-mass energy of √s̅ = 13 TeV recorded ...
    • Precise Measurement of the e⁺e⁻ → π⁺π⁻ (γ) Cross Section with the Initial-State Radiation Method at BABAR 

      Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Palano, A.; Eigen, G.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration (American Physical Society, 2012-08-28)
      A precise measurement of the cross section of the process e⁺e⁻ → π⁺π⁻ (γ) from threshold to an energy of 3 GeV is obtained with the initial-state radiation (ISR) method using 232 fb⁻¹ of data collected with the BABAR ...
    • Precision Measurement and Interpretation of Inclusive W⁺ , W⁻ and Z/γ* Production Cross Sections with the ATLAS Detector 

      Aaboud, M.; Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Abeloos, B.; AbouZeid, O. S.; Izen, Joseph M.; Meirose, Bernhard; Kurth, Matthew G.; Leyton, Michael; Reeves, Kendall; ATLAS Collaboration (2018-05-15)
      ATLAS measurements of two-particle correlations are presented for √s̅ = 5.02 and 13 TeV pp collisions and for √{S_{NN}} = 5.02 TeV p + Pb collisions at the LHC. The correlation functions are measured as a function of ...
    • Precision Measurement of the B→X_sγ Photon Energy Spectrum, Branching Fraction, and Direct CP Asymmetry A_{CP}(B→X_{s+d}γ) 

      Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Palano, A.; Eigen, G.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration (American Physical Society, 2012-11-09)
      The photon spectrum in the inclusive electromagnetic radiative decays of the B meson, B→X_sγ plus B→X_dγ, is studied using a data sample of (382.8 ± 4.2)×10⁶Υ(4S) →BB̄ decays collected by the BABAR experiment at SLAC. ...
    • Probing the W tb Vertex Structure in T-Channel Single-Top-Quark Production and Decay in pp Collisions at √s̅ = 8 TeV with the ATLAS Detector 

      Aaboud, M.; Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Abeloos, B.; AbouZeid, O. S.; Izen, Joseph M.; Meirose, Bernhard; Kurth, Matthew G.; Leyton, Michael; Reeves, Kendall; ATLAS Collaboration (2018-05-15)
      High-precision measurements by the ATLAS Collaboration are presented of inclusive W⁺ → ℓ⁺ν, W⁻ → ℓ⁻ν̅ and Z/γ* → ℓℓ (ℓ = e, μ) Drell-Yan production cross sections at the LHC. The data were collected in proton–proton ...
    • Production and Integration of the ATLAS Insertable B-Layer 

      Abbott, B.; Albert, J.; Alberti, F.; Alex, M.; Alimonti, G.; Alkire, S.; Allport, P.; Izen, Joseph M.; Leyton, Michael; ATLAS Collaboration (IOP Publishing Ltd, 2018-11-05)
      During the shutdown of the CERN Large Hadron Collider in 2013-2014, an additional pixel layer was installed between the existing Pixel detector of the ATLAS experiment and a new, smaller radius beam pipe. The motivation ...
    • Production of Charged Pions, Kaons, and Protons in e⁺e⁻ Annihilations into Hadrons at √s = 10.54 GeV 

      Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Lou, Xinchou; Izen, Joseph M.; BaBar Collaboration (American Physical Society, 2013-08-26)
      Inclusive production cross sections of π^±, K^± and p/p̅ per hadronic e⁺e⁻ annihilation event are measured at a center-of-mass energy of 10.54 GeV, using a relatively small sample of very high quality data from the BABAR ...