Examinando por Autor "Abud, A.A."

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    Higgs boson production cross-section measurements and their EFT interpretation in the 4 ℓ decay channel at √s= 13 TeV with the ATLAS detector
    (Springer Science and Business Media Deutschland GmbH, 2020-10) Aad, G.; Abbott, B.; Abbott, D.C.; Abud, A.A.; Abeling, K.; Abhayasinghe, D.K.; Abidi, S.H.; AbouZeid, O.S.; Abraham, N.L.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.
    Higgs boson properties are studied in the four-lepton decay channel (where lepton = e, μ) using 139 fb - 1 of proton–proton collision data recorded at s=13 TeV by the ATLAS experiment at the Large Hadron Collider. The inclusive cross-section times branching ratio for H→ ZZ∗ decay is measured to be 1.34 ± 0.12 pb for a Higgs boson with absolute rapidity below 2.5, in good agreement with the Standard Model prediction of 1.33 ± 0.08 pb. Cross-sections times branching ratio are measured for the main Higgs boson production modes in several exclusive phase-space regions. The measurements are interpreted in terms of coupling modifiers and of the tensor structure of Higgs boson interactions using an effective field theory approach. Exclusion limits are set on the CP-even and CP-odd ‘beyond the Standard Model’ couplings of the Higgs boson to vector bosons, gluons and top quarks. © 2020, The Author(s).
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    Measurement of the CP-violating phase ϕs in Bs0→J/ψϕ decays in ATLAS at 13 TeV
    (Springer Science and Business Media Deutschland GmbH, 2021-04) Aad, G.; Abbott, B.; Abbott, D.C.; Abdinov, O.; Abud, A.A.; Abeling, K.; Abhayasinghe, D.K.; Abidi, S.H.; AbouZeid, O.S.; Abraham, N.L.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Acharya, B.S.; Achkar, B.; Adachi, S.; Adam, L.; Bourdarios, C.A.; Adamczyk, L.; Adamek, L.; Adelman, J.; Adersberger, M.; Adiguzel, A.; Adorni, S.
    A measurement of the Bs0→J/ψϕ decay parameters using 80.5fb-1 of integrated luminosity collected with the ATLAS detector from 13 Te proton–proton collisions at the LHC is presented. The measured parameters include the CP-violating phase ϕs, the width difference Δ Γ s between the Bs0 meson mass eigenstates and the average decay width Γ s. The values measured for the physical parameters are combined with those from 19.2fb-1 of 7 and 8 Te data, leading to the following: ϕs=-0.087±0.036(stat.)±0.021(syst.)radΔΓs=0.0657±0.0043(stat.)±0.0037(syst.)ps-1Γs=0.6703±0.0014(stat.)±0.0018(syst.)ps-1Results for ϕs and Δ Γ s are also presented as 68% confidence level contours in the ϕs–Δ Γ s plane. Furthermore the transversity amplitudes and corresponding strong phases are measured. ϕs and Δ Γ s measurements are in agreement with the Standard Model predictions. © 2021, The Author(s).
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    Optimisation of large-radius jet reconstruction for the ATLAS detector in 13 TeV proton–proton collisions
    (Springer Science and Business Media Deutschland GmbH, 2021-04) Aad, G.; Abbott, B.; Abbott, D.C.; Abud, A.A.; Abeling, K.; Abhayasinghe, D.K.; Abidi, S.H; AbouZeid, O.S.; Abraham, N.L.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Acharya, B.S.; Achkar, B.; Adam, L.; Bourdarios, C.A.; Adamczyk, L.; Adamek, L.; Adelman, J.; Adersberger, M.; Adiguzel, A.; Adorni, S.; Adye, T.; Affolder, A.A.
    Jet substructure has provided new opportunities for searches and measurements at the LHC, and has seen continuous development since the optimization of the large-radius jet definition used by ATLAS was performed during Run 1. A range of new inputs to jet reconstruction, pile-up mitigation techniques and jet grooming algorithms motivate an optimisation of large-radius jet reconstruction for ATLAS. In this paper, this optimisation procedure is presented, and the performance of a wide range of large-radius jet definitions is compared. The relative performance of these jet definitions is assessed using metrics such as their pileup stability, ability to identify hadronically decaying W bosons and top quarks with large transverse momenta. A new type of jet input object, called a ‘unified flow object’ is introduced which combines calorimeter- and inner-detector-based signals in order to achieve optimal performance across a wide kinematic range. Large-radius jet definitions are identified which significantly improve on the current ATLAS baseline definition, and their modelling is studied using pp collisions recorded by the ATLAS detector at s=13TeV during 2017. © 2021, The Author(s).
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    Search for pair production of scalar leptoquarks decaying into first- or second-generation leptons and top quarks in proton–proton collisions at √s = 13 TeV with the ATLAS detector
    (Springer Science and Business Media Deutschland GmbH, 2021-04) Aad, G.; Abbott, B.; Abbott, D.C.; Abud, A.A.; Abeling, K.; Abhayasinghe, D.K.; Abidi, S.H.; AbouZeid, O.S.; Abraham, N.L.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Acharya, B.S.; Achkar, B.; Adam, L.; Bourdarios, C.A.; Adamczyk, L.; Adamek, L.; Adelman, J.; Adorni, S.; Adiguzel, A.; Adye, T.; Affolder, A.A.; Afik, Y.
    A search for pair production of scalar leptoquarks, each decaying into either an electron or a muon and a top quark, is presented. This is the first leptoquark search using ATLAS data to investigate top-philic cross-generational couplings that could provide explanations for recently observed anomalies in B meson decays. This analysis targets high leptoquark masses which cause the decay products of each resultant top quark to be contained within a single high-pT large-radius jet. The full Run 2 dataset is exploited, consisting of 139fb-1 of data collected from proton–proton collisions at s=13TeV from 2015 to 2018 with the ATLAS detector at the CERN Large Hadron Collider. In the absence of any significant deviation from the background expectation, lower limits on the leptoquark masses are set at 1480GeV and 1470GeV for the electron and muon channel, respectively. © 2021, The Author(s).