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Open Access Publications from the University of California

Scholarly Works (680 results)

  • Article
  • Peer Reviewed
UC San Francisco Previously Published Works (2016)
Patients with autism spectrum disorder (ASD) are at increased risk for fracture, and peri-pubertal boys with ASD have lower bone mineral density (BMD) than controls. Data are lacking regarding BMD in older adolescents with ASD. We compared BMD using dual-energy X-ray absorptiometry in 9 adolescents/young adults with ASD against 9 typically developing matched controls. Patients with ASD and controls were excluded if they had other underlying conditions that may affect bone. Compared to controls, patients with ASD had (i) lower femoral neck and hip BMD Z-scores, and (ii) lower spine, femoral neck and hip height adjusted BMD Z-scores even after controlling for BMI. Understanding the underlying pathophysiology will be key to developing therapies to improve BMD and reduce fracture risk.
    Cover page: Bone Density in Adolescents and Young Adults with Autism Spectrum Disorders.
    • Article
    • Peer Reviewed
    UC Santa Cruz Previously Published Works (2020)
    A mistake was identified for the paper [1] in the treatment of the radion [2] cross-sections, which resulted in multiple changes.
      • Article
      • Peer Reviewed
      UC Irvine Previously Published Works (2016)
      The results of a search for the top squark, the supersymmetric partner of the top quark, in final states with one isolated electron or muon, jets, and missing transverse momentum are reported. The search uses the 2015 LHC pp collision data at a center-of-mass energy of s=13 TeV recorded by the ATLAS detector and corresponding to an integrated luminosity of 3.2 fb-1. The analysis targets two types of signal models: gluino-mediated pair production of top squarks with a nearly mass-degenerate top squark and neutralino and direct pair production of top squarks, decaying to the top quark and the lightest neutralino. The experimental signature in both signal scenarios is similar to that of a top quark pair produced in association with large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits on gluino and top squark masses are set at 95% confidence level. The results extend the LHC run-1 exclusion limit on the gluino mass up to 1460 GeV in the gluino-mediated scenario in the high gluino and low top squark mass region and add an excluded top squark mass region from 745 to 780 GeV for the direct top squark model with a massless lightest neutralino. The results are also reinterpreted to set exclusion limits in a model of vectorlike top quarks.
        Cover page: Search for top squarks in final states with one isolated lepton, jets, and missing transverse momentum in s=13 TeV pp collisions with the ATLAS detector
        • Article
        • Peer Reviewed
        UC Santa Cruz Previously Published Works (2015)
        The final ATLAS Run 1 measurements of Higgs boson production and couplings in the decay channel H → ZZ∗ → l+l-l'+l'-, where l, l' = e or μ, are presented. These measurements were performed using pp collision data corresponding to integrated luminosities of 4.5 and 20.3 fb-1 at center-of-mass energies of 7 and 8 TeV, respectively, recorded with the ATLAS detector at the LHC. The H → ZZ∗ → 4l signal is observed with a significance of 8.1 standard deviations, with an expectation of 6.2 standard deviations, at mH = 125.36 GeV, the combined ATLAS measurement of the Higgs boson mass from the H → γγ and H → ZZ∗ → 4l channels. The production rate relative to the Standard Model expectation, the signal strength, is measured in four different production categories in the H → ZZ∗ → 4l channel. The measured signal strength, at this mass, and with all categories combined, is 1.44+0.40-0.33. The signal strength for Higgs boson production in gluon fusion or in association with tt or bb pairs is found to be 1.7+0.5-0.4, while the signal strength for vector-boson fusion combined with WH/ZH associated production is found to be 0.3+1.6-0.9.
          Cover page: Measurements of Higgs boson production and couplings in the four-lepton channel in pp collisions at center-of-mass energies of 7 and 8 TeV with the ATLAS detector
          • Article
          • Peer Reviewed
          UC Santa Cruz Previously Published Works (2015)
          High transverse momentum jets produced in pp collisions at a centre of mass energy of 7 TeV are used to measure the transverse energy-energy correlation function and its associated azimuthal asymmetry. The data were recorded with the ATLAS detector at the LHC in the year 2011 and correspond to an integrated luminosity of 158 pb-1. The selection criteria demand the average transverse momentum of the two leading jets in an event to be larger than 250 GeV. The data at detector level are well described by Monte Carlo event generators. They are unfolded to the particle level and compared with theoretical calculations at next-to-leading-order accuracy. The agreement between data and theory is good and provides a precision test of perturbative Quantum Chromodynamics at large momentum transfers. From this comparison, the strong coupling constant given at the Z boson mass is determined to be as(mZ)=0.1173±0.0010 (exp.) -0.0026+0.0065 (theo.).
            Cover page: Measurement of transverse energy–energy correlations in multi-jet events in pp collisions at s=7 TeV using the ATLAS detector and determination of the strong coupling constant αs(mZ)
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            • Peer Reviewed
            UC Santa Cruz Previously Published Works (2015)
              Cover page: Erratum to: Search for production of WW / WZ resonances decaying to a lepton, neutrino and jets in pp collisions at s=8 TeV with the ATLAS detector
              • Article
              • Peer Reviewed
              UC Santa Cruz Previously Published Works (2014)
              ATLAS measurements of the azimuthal anisotropy in lead-lead collisions at [Formula: see text] TeV are shown using a dataset of approximately 7 [Formula: see text]b[Formula: see text] collected at the LHC in 2010. The measurements are performed for charged particles with transverse momenta [Formula: see text] GeV and in the pseudorapidity range [Formula: see text]. The anisotropy is characterized by the Fourier coefficients, [Formula: see text], of the charged-particle azimuthal angle distribution for [Formula: see text]-4. The Fourier coefficients are evaluated using multi-particle cumulants calculated with the generating function method. Results on the transverse momentum, pseudorapidity and centrality dependence of the [Formula: see text] coefficients are presented. The elliptic flow, [Formula: see text], is obtained from the two-, four-, six- and eight-particle cumulants while higher-order coefficients, [Formula: see text] and [Formula: see text], are determined with two- and four-particle cumulants. Flow harmonics [Formula: see text] measured with four-particle cumulants are significantly reduced compared to the measurement involving two-particle cumulants. A comparison to [Formula: see text] measurements obtained using different analysis methods and previously reported by the LHC experiments is also shown. Results of measurements of flow fluctuations evaluated with multi-particle cumulants are shown as a function of transverse momentum and the collision centrality. Models of the initial spatial geometry and its fluctuations fail to describe the flow fluctuations measurements.
                Cover page: Measurement of flow harmonics with multi-particle cumulants in Pb+Pb collisions at sNN=2.76 TeV with the ATLAS detector
                • Article
                • Peer Reviewed
                UC Irvine Previously Published Works (2016)
                A measurement of the Bs0decay parameters in the Bs0→ J/ψϕ channel using an integrated luminosity of 14.3 fb−1collected by the ATLAS detector from 8 TeV pp collisions at the LHC is presented. The measured parameters include the CP -violating phase ϕs, the decay width Γs and the width difference between the mass eigenstates ΔΓs. The values measured for the physical parameters are statistically combined with those from 4.9 fb−1of 7 TeV data, leading to the following: Φs = -0.090 ± 0.078 (stat.) ± (syst.) rad Δ Γs = 0.085 ± 0.011 (stat.) ± 0.007 (syst.) Ps-1 Δ Γs = 0.675 ± 0.003 (stat.) ± 0.03 (syst.) Ps-1 In the analysis the parameter ΔΓs is constrained to be positive. Results for ϕs and ΔΓs are also presented as 68% and 95% likelihood contours in the ϕs-ΔΓs plane. Also measured in this decay channel are the transversity amplitudes and corresponding strong phases. All measurements are in agreement with the Standard Model predictions.[Figure not available: see fulltext.]
                  Cover page: Measurement of the CP-violating phase ϕs and the Bs0 meson decay width difference with Bs0 → J/ψϕ decays in ATLAS
                  • Article
                  • Peer Reviewed
                  UC Berkeley Previously Published Works (2020)
                  The PreProcessor of the ATLAS Level-1 Calorimeter Trigger prepares the analogue trigger signals sent from the ATLAS calorimeters by digitising, synchronising, and calibrating them to reconstruct transverse energy deposits, which are then used in further processing to identify event features. During the first long shutdown of the LHC from 2013 to 2014, the central components of the PreProcessor, the Multichip Modules, were replaced by upgraded versions that feature modern ADC and FPGA technology to ensure optimal performance in the high pile-up environment of LHC Run 2. This paper describes the features of the new Multichip Modules along with the improvements to the signal processing achieved.
                    Cover page: Performance of the upgraded PreProcessor of the ATLAS Level-1 Calorimeter Trigger
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                    • Peer Reviewed
                    UC Irvine Previously Published Works (2016)
                    A search is performed for a heavy particle decaying into different flavour dilepton pairs ([Formula: see text], [Formula: see text] or [Formula: see text]), using 3.2 fb[Formula: see text] of proton-proton collision data at [Formula: see text] TeV collected in 2015 by the ATLAS detector at the Large Hadron Collider. No excess over the Standard Model prediction is observed. Limits at the 95 % credibility level are set on the mass of a [Formula: see text] boson with lepton-flavour-violating couplings at 3.0, 2.7 and 2.6 TeV, and on the mass of a supersymmetric [Formula: see text] sneutrino with R-parity-violating couplings at 2.3, 2.2 and 1.9 TeV, for [Formula: see text], [Formula: see text] and [Formula: see text] final states, respectively. The results are also interpreted as limits on the threshold mass for quantum black hole production.
                      Cover page: Search for new phenomena in different-flavour high-mass dilepton final states in pp collisions at s=13 Tev with the ATLAS detector
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