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Open Access Publications from the University of California

Scholarly Works (397 results)

  • Article
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UC Santa Cruz Previously Published Works (2011)
The inclusive J/Ψ production cross-section and fraction of J/Ψ mesons produced in B-hadron decays are measured in proton-proton collisions at √s=7 TeV with the ATLAS detector at the LHC, as a function of the transverse momentum and rapidity of the J/Ψ, using 2.3 pb-1 of integrated luminosity. The cross-section is measured from a minimum pT of 1 GeV to a maximum of 70 GeV and for rapidities within |y|<2.4 giving the widest reach of any measurement of J/Ψ production to date. The differential production cross-sections of prompt and non-prompt J/Ψ are separately determined and are compared to Colour Singlet NNLO*, Colour Evaporation Model, and FONLL predictions. © 2011 CERN.
    Cover page: Measurement of the differential cross-sections of inclusive, prompt and non-prompt J/ψ production in proton–proton collisions at s=7 TeVCreative Commons 'BY' version 4.0 license
    • Article
    • Peer Reviewed
    UC Berkeley Previously Published Works (2012)
    A search for a Standard Model Higgs boson decaying via H→ZZ→ℓ+ℓ−νν¯ where ℓ represents electrons or muons, is presented. It is based on proton-proton collision data at s=7 TeV, collected by the ATLAS experiment at the LHC during 2011 and corresponding to an integrated luminosity of 4.7 fb−1. The data agree with the expected Standard Model backgrounds. Upper limits on the Higgs boson production cross section are derived for Higgs boson masses between 200 GeV and 600 GeV and the production of a Standard Model Higgs boson with a mass in the range 319–558 GeV is excluded at the 95% confidence level.
      Cover page: Search for a standard model Higgs boson in the H→ZZ→ℓ+ℓ−νν¯ decay channel using 4.7&nbsp;fb−1 of s=7&nbsp;TeV data with the ATLAS detectorCreative Commons 'BY' version 4.0 license
      • Article
      • Peer Reviewed
      UC Irvine Previously Published Works (2012)
      This Letter describes the measurement of elliptic flow of charged particles in lead-lead collisions at sNN=2.76 TeV using the ATLAS detector at the Large Hadron Collider (LHC). The results are based on an integrated luminosity of approximately 7 μb-1. Elliptic flow is measured over a wide region in pseudorapidity, |η|<2.5, and over a broad range in transverse momentum, 0.5
        Cover page: Measurement of the pseudorapidity and transverse momentum dependence of the elliptic flow of charged particles in lead–lead collisions at sNN=2.76&nbsp;TeV with the ATLAS detectorCreative Commons 'BY' version 4.0 license
        • Article
        • Peer Reviewed
        UC Santa Cruz Previously Published Works (2013)
        A search for new particles that decay into top quark pairs (tt) is performed with the ATLAS experiment at the LHC using an integrated luminosity of 4.7 fb–1of proton–proton (pp) collision data collected at a center-of-mass energy √s = 7 TeV. In the tt̄→ WbWb decay, the lepton plus jets final state is used, where one W boson decays leptonically and the other hadronically. The tt̄system is reconstructed using both small-radius and large-radius jets, the latter being supplemented by a jet substructure analysis. A search for local excesses in the number of data events compared to the Standard Model expectation in the tt̄invariant mass spectrum is performed. No evidence for a tt̄resonance is found and 95% credibility-level limits on the production rate are determined for massive states predicted in two benchmark models. The upper limits on the cross section times branching ratio of a narrow Z′ resonance range from 5.1 pb for a boson mass of 0.5 TeV to 0.03 pb for a mass of 3 TeV. A narrow leptophobic topcolor Z′ resonance with a mass below 1.74 TeV is excluded. Limits are also derived for a broad color-octet resonance with Γ/m = 15.3%. A Kaluza–Klein excitation of the gluon in a Randall–Sundrum model is excluded for masses below 2.07 TeV.
          Cover page: Search for tt¯ resonances in the lepton plus jets final state with ATLAS using 4.7 fb-1 of pp collisions at s=7 TeVCreative Commons 'BY' version 4.0 license
          • Article
          • Peer Reviewed