Yazar "Aad, G" seçeneğine göre listele

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  • Küçük Resim
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    Combination of searches for heavy spin-1 resonances using 139 fb−1 of proton-proton collision data at s = 13 TeV with the ATLAS detector
    (Springer Science and Business Media Deutschland GmbH, 2024) Aad, G; Aakvaag, E; Abbott, B; Abeling, K.; Beddall, Andrew John; Çetin, Serkant Ali; Öztürk, Sertaç; Şimşek, Sinem; Uysal, Zekeriya
    A combination of searches for new heavy spin-1 resonances decaying into different pairings of W, Z, or Higgs bosons, as well as directly into leptons or quarks, is presented. The data sample used corresponds to 139 fb−1 of proton-proton collisions at s = 13 TeV collected during 2015–2018 with the ATLAS detector at the CERN Large Hadron Collider. Analyses selecting quark pairs (qq, bb, tt¯, and tb) or third-generation leptons (τν and ττ) are included in this kind of combination for the first time. A simplified model predicting a spin-1 heavy vector-boson triplet is used. Cross-section limits are set at the 95% confidence level and are compared with predictions for the benchmark model. These limits are also expressed in terms of constraints on couplings of the heavy vector-boson triplet to quarks, leptons, and the Higgs boson. The complementarity of the various analyses increases the sensitivity to new physics, and the resulting constraints are stronger than those from any individual analysis considered. The data exclude a heavy vector-boson triplet with mass below 5.8 TeV in a weakly coupled scenario, below 4.4 TeV in a strongly coupled scenario, and up to 1.5 TeV in the case of production via vector-boson fusion. © The Author(s) 2024.
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    Measurement of 𝑡-channel single-top-quark production in 𝑝𝑝 collisions at √𝑠 = 5.02 TeV with the ATLAS detector
    (Elsevier B.V., 2024) Aad, G; Abbott, B; Abeling, K.; Beddall, Andrew John; Çetin, Serkant Ali; Öztürk, Sertaç; Şimşek, Sinem
    The observation of the electroweak production of single-top-quarks is made using 255 pb−1 of proton-proton collision data recorded at s=5.02 TeV with the ATLAS detector at the Large Hadron Collider. An event selection is used to identify single-top-quark candidates arising from t-channel production with the top quark decaying semi-leptonically. Events passing the selection are then used to measure the inclusive cross-section for the combined production of single-top-quarks and antiquarks, σ(tq+t¯q), and the ratio Rt between these two. They are measured to be σ(tq+t¯q)=27.1−4.1 +4.4(stat.)−3.7 +4.4(syst.) pb and Rt=2.73−0.82 +1.43(stat.)−0.29 +1.01(syst.). The individual single-top-quark (tq) and single-top-antiquark (t¯q) production cross-sections are measured to be σ(tq)=19.8−3.1 +3.9(stat.)−2.2 +2.9(syst.) pb and σ(t¯q)=7.3−2.1 +3.2(stat.)−1.5 +2.8(syst.) pb. All measurements are in good agreement with the Standard Model predictions. © 2024 The Author(s)
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    Search for neutral long-lived particles in pp collisions at ?s = 13 TeV that decay into displaced hadronic jets in the ATLAS calorimeter
    (Springer, 2022) Çetin, Serkant Ali; Beddall, Andrew John; Celebi, E.; Aad, G; Abbott, D.C.; Aboulhorma, A.; Abramowicz, H.; Abreu, H.; Bella, G.; Beloborodov, K.; Beretta, M.; Chan, W.S.; Chen, C.; Kolcu, Onur Buğra
    A search for decays of pair-produced neutral long-lived particles (LLPs) is presented using 139 fb?1 of proton-proton collision data collected by the ATLAS detector at the LHC in 2015–2018 at a centre-of-mass energy of 13 TeV. Dedicated techniques were developed for the reconstruction of displaced jets produced by LLPs decaying hadronically in the ATLAS hadronic calorimeter. Two search regions are defined for different LLP kinematic regimes. The observed numbers of events are consistent with the expected background, and limits for several benchmark signals are determined. For a SM Higgs boson with a mass of 125 GeV, branching ratios above 10% are excluded at 95% confidence level for values of c times LLP mean proper lifetime in the range between 20 mm and 10 m depending on the model. Upper limits are also set on the cross-section times branching ratio for scalars with a mass of 60 GeV and for masses between 200 GeV and 1 TeV. [Figure not available: see fulltext.] © 2022, The Author(s).