407 research outputs found

    Trap-Assisted Tunneling in the Schottky Barrier

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    The paper presents a new way how to calculate the currents in a Schottky barrier. The novel phenomeno-logical model extends the Shockley-Read-Hall recombi-nation-generation theory of trap-assisted tunneling. The proposed approach explains the occurrence of large leakage currents in Schottky structures on wide band semi-conductors with a high Schottky barrier (above 1 eV) and with a high density of traps. Under certain conditions, trap-assisted tunneling (TAT) plays a more important role than direct tunneling

    Developing collaborative professionalism : an investigation of status differentiation in academic organizations in knowledge transfer partnerships

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    In recent years there has been a significant growth in knowledge transfer partnerships to improve the quality and timeliness of healthcare. These activities require an increasing level of interdependence between academic and healthcare professionals, with important implications for human resource management. To understand these knowledge transfer partnerships, we conducted an in-depth longitudinal study based on 99 interviews and 5 focus-group workshops across academic and healthcare professionals in nine university-based knowledge transfer partnerships in England. We explore how academic professionals of lower and higher status organizations develop a new form of professional work, based on the principles of collaborative professionalism, during their involvement in partnerships with healthcare professionals. We illuminate how the interdependent work between academic professionals and healthcare professionals in the development of a new academic specialization is shaped by the status of their organization

    Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

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    A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV

    Search for direct stau production in events with two hadronic tau-leptons in root s=13 TeV pp collisions with the ATLAS detector

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    A search for the direct production of the supersymmetric partners ofτ-leptons (staus) in final stateswith two hadronically decayingτ-leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of139fb−1, recorded with the ATLAS detector at the LargeHadron Collider at a center-of-mass energy of 13 TeV. No significant deviation from the expected StandardModel background is observed. Limits are derived in scenarios of direct production of stau pairs with eachstau decaying into the stable lightest neutralino and oneτ-lepton in simplified models where the two staumass eigenstates are degenerate. Stau masses from 120 GeV to 390 GeV are excluded at 95% confidencelevel for a massless lightest neutralino

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    A search for the dimuon decay of the Standard Model Higgs boson with the ATLAS detector

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    A search for the dimuon decay of the Standard Model (SM) Higgs boson is performed using data corresponding to an integrated luminosity of 139 fb(-1) collected with the ATLAS detector in Run 2 pp collisions at root s = 13 TeV at the Large Hadron Collider. The observed (expected) significance over the background-only hypothesis for a Higgs boson with a mass of 125.09 GeV is 2.0 sigma (1.7 sigma). The observed upper limit on the cross section times branching ratio for pp -> H -> mu mu is 2.2 times the SM prediction at 95% confidence level, while the expected limit on a H -> mu mu signal assuming the absence (presence) of a SM signal is 1.1(2.0). The best-fit value of the signal strength parameter, defined as the ratio of the observed signal yield to the one expected in the SM, is mu = 1.2 +/- 0.6. (C) 2020 The Author(s). Published by Elsevier B.V

    Performance of electron and photon triggers in ATLAS during LHC Run 2

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    Electron and photon triggers covering transverseenergies from 5 GeV to several TeV are essential for theATLAS experiment to record signals for a wide variety ofphysics: from Standard Model processes to searches for newphenomena in both proton–proton and heavy-ion collisions.To cope with a fourfold increase of peak LHC luminosityfrom 2015 to 2018 (Run 2), to 2.1×1034cm−2s−1, anda similar increase in the number of interactions per beam-crossing to about 60, trigger algorithms and selections wereoptimised to control the rates while retaining a high effi-ciency for physics analyses. For proton–proton collisions, thesingle-electron trigger efficiency relative to a single-electronoffline selection is at least 75% for an offline electron of31 GeV, and rises to 96% at 60 GeV; the trigger efficiency ofa 25 GeV leg of the primary diphoton trigger relative to a tightoffline photon selection is more than 96% for an offline pho-ton of 30 GeV. For heavy-ion collisions, the primary electronand photon trigger efficiencies relative to the correspondingstandard offline selections are at least 84% and 95%, respec-tively, at 5 GeV above the corresponding trigger threshold
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