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Publication Open Access Search for resonances in diphoton events at √s=13 TeV with the ATLAS detector(Springer Verlag [email protected], 2016) The Atlas Collaboration; Aaboud, M.; Aad, Georges; Abbott, Brad K.; Abdallah, Jalal Mohamad; Abdinov, O. B.; Abeloos, Baptiste; Aben, R.; AbouZeid, O. S.; Abraham, Nicola L.; The Atlas Collaboration, null, Universitatea Transilvania din Brașov, Brasov, Romania, University Politehnica of Bucharest, Bucharest, Romania, Dep Fisica and CEFITEC, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Caparica, Portugal, Organisation Européenne pour la Recherche Nucléaire, Geneva, Switzerland; Aaboud, M., Université Mohammed Premier Oujda, Oujda, Morocco; Aad, Georges, Centre de Physique des Particules de Marseille, Marseille, France; Abbott, Brad K., Homer L. Dodge Department of Physics and Astronomy, The University of Oklahoma, Norman, United States; Abdallah, Jalal Mohamad, University of Iowa, Iowa City, United States; Abdinov, O. B., Azerbaijan National Academy of Sciences, Baku, Azerbaijan; Abeloos, Baptiste, Laboratoire de l'Accélérateur Linéaire, Orsay, France; Aben, R., Universiteit van Amsterdam, Amsterdam, Netherlands; AbouZeid, O. S., Santa Cruz Institute for Particle Physics, Santa Cruz, United States; Abraham, Nicola L., Department of Physics and Astronomy, University of Sussex, Brighton, United KingdomSearches for new resonances decaying into two photons in the ATLAS experiment at the CERN Large Hadron Collider are described. The analysis is based on proton-proton collision data corresponding to an integrated luminosity of 3.2 fb−1 at s=13 TeV recorded in 2015. Two searches are performed, one targeted at a spin-2 particle of mass larger than 500 GeV, using Randall-Sundrum graviton states as a benchmark model, and one optimized for a spin-0 particle of mass larger than 200 GeV. Varying both the mass and the decay width, the most significant deviation from the background-only hypothesis is observed at a diphoton invariant mass around 750 GeV with local significances of 3.8 and 3.9 standard deviations in the searches optimized for a spin-2 and spin-0 particle, respectively. The global significances are estimated to be 2.1 standard deviations for both analyses. The consistency between the data collected at 13 TeV and 8 TeV is also evaluated. Limits on the production cross section times branching ratio to two photons for the two resonance types are reported.[Figure not available: see fulltext.] © 2019 Elsevier B.V., All rights reserved.Publication Open Access Search for direct top squark pair production in events with a Higgs or Z boson, and missing transverse momentum in √s=13 TeV pp collisions with the ATLAS detector(Springer Verlag, 2017) Aaboud, M.; Aad, Georges; Abbott, Brad K.; Abdinov, O. B.; Abeloos, Baptiste; Abidi, Syed Hani; AbouZeid, O. S.; Abraham, Nicola L.; Abramowicz, Halina; Abreu, Henso; Aaboud, M., Faculty of Science, Université Mohammed Premier Oujda, Oujda, Morocco; Aad, Georges, Centre de Physique des Particules de Marseille, Marseille, France; Abbott, Brad K., The University of Oklahoma, Norman, United States; Abdinov, O. B., Azerbaijan National Academy of Sciences, Baku, Azerbaijan; Abeloos, Baptiste, Laboratoire de l'Accélérateur Linéaire, Orsay, France; Abidi, Syed Hani, University of Toronto, Toronto, Canada; AbouZeid, O. S., Santa Cruz Institute for Particle Physics, Santa Cruz, United States; Abraham, Nicola L., University of Sussex, Brighton, United Kingdom; Abramowicz, Halina, Tel Aviv University, Tel Aviv-Yafo, Israel; Abreu, Henso, Department of Physics, Technion - Israel Institute of Technology, Haifa, IsraelA search for direct top squark pair production resulting in events with either a same-flavour opposite-sign dilepton pair with invariant mass compatible with a Z boson or a pair of jets compatible with a Standard Model (SM) Higgs boson (h) is presented. Requirements on the missing transverse momentum, together with additional selections on leptons, jets, jets identified as originating from b-quarks are imposed to target the other decay products of the top squark pair. The analysis is performed using proton-proton collision data at s=13 TeV collected with the ATLAS detector at the LHC in 2015–2016, corresponding to an integrated luminosity of 36.1 fb−1. No excess is observed in the data with respect to the SM predictions. The results are interpreted in two sets of models. In the first set, direct production of pairs of lighter top squarks (t 1) with long decay chains involving Z or Higgs bosons is considered. The second set includes direct pair production of the heavier top squark pairs (t 2) decaying via t 2→ Zt 1 or t 2→ ht 1. The results exclude at 95% confidence level t 2 and t 1 masses up to about 800 GeV, extending the exclusion region of supersymmetric parameter space covered by previous LHC searches.[Figure not available: see fulltext.]. © 2025 Elsevier B.V., All rights reserved.Publication Open Access Search for new phenomena in a lepton plus high jet multiplicity final state with the ATLAS experiment using √s=13 TeV proton-proton collision data(Springer Verlag, 2017) Aaboud, M.; Aad, Georges; Abbott, Brad K.; Abdinov, O. B.; Abeloos, Baptiste; Abidi, Syed Hani; AbouZeid, O. S.; Abraham, Nicola L.; Abramowicz, Halina; Abreu, Henso; Aaboud, M., Faculty of Science, Université Mohammed Premier Oujda, Oujda, Morocco; Aad, Georges, Centre de Physique des Particules de Marseille, Marseille, France; Abbott, Brad K., The University of Oklahoma, Norman, United States; Abdinov, O. B., Azerbaijan National Academy of Sciences, Baku, Azerbaijan; Abeloos, Baptiste, Laboratoire de l'Accélérateur Linéaire, Orsay, France; Abidi, Syed Hani, University of Toronto, Toronto, Canada; AbouZeid, O. S., Santa Cruz Institute for Particle Physics, Santa Cruz, United States; Abraham, Nicola L., University of Sussex, Brighton, United Kingdom; Abramowicz, Halina, Tel Aviv University, Tel Aviv-Yafo, Israel; Abreu, Henso, Department of Physics, Technion - Israel Institute of Technology, Haifa, IsraelA search for new phenomena in final states characterized by high jet multiplicity, an isolated lepton (electron or muon) and either zero or at least three b-tagged jets is presented. The search uses 36.1 fb−1 of s=13 TeV proton-proton collision data collected by the ATLAS experiment at the Large Hadron Collider in 2015 and 2016. The dominant sources of background are estimated using parameterized extrapolations, based on observables at medium jet multiplicity, to predict the b-tagged jet multiplicity distribution at the higher jet multiplicities used in the search. No significant excess over the Standard Model expectation is observed and 95% confidence-level limits are extracted constraining four simplified models of R-parity-violating supersymmetry that feature either gluino or top-squark pair production. The exclusion limits reach as high as 2.1 TeV in gluino mass and 1.2 TeV in top-squark mass in the models considered. In addition, an upper limit is set on the cross-section for Standard Model tt¯ tt¯ production of 60 fb (6.5 × the Standard Model prediction) at 95% confidence level. Finally, model-independent limits are set on the contribution from new phenomena to the signal-region yields.[Figure not available: see fulltext.]. © 2025 Elsevier B.V., All rights reserved.Publication Open Access Search for new high-mass phenomena in the dilepton final state using 36 fb−1 of proton-proton collision data at √s=13 TeV with the ATLAS detector(Springer Verlag, 2017) Aaboud, M.; Aad, Georges; Abbott, Brad K.; Abdinov, O. B.; Abeloos, Baptiste; Abidi, Syed Hani; AbouZeid, O. S.; Abraham, Nicola L.; Abramowicz, Halina; Abreu, Henso; Aaboud, M., Faculty of Science, Université Mohammed Premier Oujda, Oujda, Morocco; Aad, Georges, Centre de Physique des Particules de Marseille, Marseille, France; Abbott, Brad K., The University of Oklahoma, Norman, United States; Abdinov, O. B., Azerbaijan National Academy of Sciences, Baku, Azerbaijan; Abeloos, Baptiste, Laboratoire de l'Accélérateur Linéaire, Orsay, France; Abidi, Syed Hani, University of Toronto, Toronto, Canada; AbouZeid, O. S., Santa Cruz Institute for Particle Physics, Santa Cruz, United States; Abraham, Nicola L., University of Sussex, Brighton, United Kingdom; Abramowicz, Halina, Tel Aviv University, Tel Aviv-Yafo, Israel; Abreu, Henso, Department of Physics, Technion - Israel Institute of Technology, Haifa, IsraelA search is conducted for new resonant and non-resonant high-mass phenomena in dielectron and dimuon final states. The search uses 36.1 fb−1 of proton-proton collision data, collected at s=13 TeV by the ATLAS experiment at the LHC in 2015 and 2016. No significant deviation from the Standard Model prediction is observed. Upper limits at 95% credibility level are set on the cross-section times branching ratio for resonances decaying into dileptons, which are converted to lower limits on the resonance mass, up to 4.1 TeV for the E6-motivated Zχ ′. Lower limits on the qqℓℓ contact interaction scale are set between 2.4 TeV and 40 TeV, depending on the model. © 2025 Elsevier B.V., All rights reserved.Publication Open Access Search for new phenomena with large jet multiplicities and missing transverse momentum using large-radius jets and flavour-tagging at ATLAS in 13 TeV pp collisions(Springer Verlag, 2017) Aaboud, M.; Aad, Georges; Abbott, Brad K.; Abdinov, O. B.; Abeloos, Baptiste; Abidi, Syed Hani; AbouZeid, O. S.; Abraham, Nicola L.; Abramowicz, Halina; Abreu, Henso; Aaboud, M., Faculty of Science, Université Mohammed Premier Oujda, Oujda, Morocco; Aad, Georges, Centre de Physique des Particules de Marseille, Marseille, France; Abbott, Brad K., The University of Oklahoma, Norman, United States; Abdinov, O. B., Azerbaijan National Academy of Sciences, Baku, Azerbaijan; Abeloos, Baptiste, Laboratoire de l'Accélérateur Linéaire, Orsay, France; Abidi, Syed Hani, University of Toronto, Toronto, Canada; AbouZeid, O. S., Santa Cruz Institute for Particle Physics, Santa Cruz, United States; Abraham, Nicola L., University of Sussex, Brighton, United Kingdom; Abramowicz, Halina, Tel Aviv University, Tel Aviv-Yafo, Israel; Abreu, Henso, Department of Physics, Technion - Israel Institute of Technology, Haifa, IsraelA search is presented for particles that decay producing a large jet multiplicity and invisible particles. The event selection applies a veto on the presence of isolated electrons or muons and additional requirements on the number of b-tagged jets and the scalar sum of masses of large-radius jets. Having explored the full ATLAS 2015-2016 dataset of LHC proton-proton collisions at s=13 TeV, which corresponds to 36.1 fb−1 of integrated luminosity, no evidence is found for physics beyond the Standard Model. The results are interpreted in the context of simplified models inspired by R-parity-conserving and R-parity-violating supersymmetry, where gluinos are pair-produced. More generic models within the phenomenological minimal supersymmetric Standard Model are also considered. © 2025 Elsevier B.V., All rights reserved.Publication Open Access Search for additional heavy neutral Higgs and gauge bosons in the ditau final state produced in 36 fb−1 of pp collisions at √s=13 TeV with the ATLAS detector(Springer Verlag, 2018) Aaboud, M.; Aad, Georges; Abbott, Brad K.; Abdinov, O. B.; Abeloos, Baptiste; Abidi, Syed Hani; AbouZeid, O. S.; Abraham, Nicola L.; Abramowicz, Halina; Abreu, Henso; Aaboud, M., Faculté des Sciences Aïn Chock, Casablanca, Morocco; Aad, Georges, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom; Abbott, Brad K., Faculty of Science, Okayama University, Okayama, Japan; Abdinov, O. B., Azerbaijan National Academy of Sciences, Baku, Azerbaijan; Abeloos, Baptiste, Center for High Energy Physics, University of Oregon, Eugene, United States; Abidi, Syed Hani, Graduate School of Science and Technology, Tokyo Metropolitan University, Hachioji, Japan; AbouZeid, O. S., Faculty of Science, Université Mohammed Premier Oujda, Oujda, Morocco; Abraham, Nicola L., Oskar Klein Centre, Stockholm, Sweden; Abramowicz, Halina, School of Physics, The University of Sydney, Sydney, Australia; Abreu, Henso, University of Sussex, Brighton, United KingdomA search for heavy neutral Higgs bosons and Z′ bosons is performed using a data sample corresponding to an integrated luminosity of 36.1 fb−1 from proton-proton collisions at s=13 TeV recorded by the ATLAS detector at the LHC during 2015 and 2016. The heavy resonance is assumed to decay to τ+τ− with at least one tau lepton decaying to final states with hadrons and a neutrino. The search is performed in the mass range of 0.2-2.25 TeV for Higgs bosons and 0.2-4.0 TeV for Z′ bosons. The data are in good agreement with the background predicted by the Standard Model. The results are interpreted in benchmark scenarios. In the context of the hMSSM scenario, the data exclude tan β > 1.0 for mA = 0.25 TeV and tan β > 42 for mA = 1.5 TeV at the 95% confidence level. For the Sequential Standard Model, ZSSM′ with mZ′ < 2.42 TeV is excluded at 95% confidence level, while ZNU′ with mZ ′ < 2.25 TeV is excluded for the non-universal G(221) model that exhibits enhanced couplings to third-generation fermions. © 2025 Elsevier B.V., All rights reserved.Publication Open Access Searches for heavy ZZ and ZW resonances in the ℓℓqq and ννqq final states in pp collisions at √s=13 TeV with the ATLAS detector(Springer Verlag, 2018) Aaboud, M.; Aad, Georges; Abbott, Brad K.; Abdinov, O. B.; Abeloos, Baptiste; Abidi, Syed Hani; AbouZeid, O. S.; Abraham, Nicola L.; Abramowicz, Halina; Abreu, Henso; Aaboud, M., Faculté des Sciences Aïn Chock, Casablanca, Morocco; Aad, Georges, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom; Abbott, Brad K., Faculty of Science, Okayama University, Okayama, Japan; Abdinov, O. B., Azerbaijan National Academy of Sciences, Baku, Azerbaijan; Abeloos, Baptiste, Center for High Energy Physics, University of Oregon, Eugene, United States; Abidi, Syed Hani, Graduate School of Science and Technology, Tokyo Metropolitan University, Hachioji, Japan; AbouZeid, O. S., Faculty of Science, Université Mohammed Premier Oujda, Oujda, Morocco; Abraham, Nicola L., Oskar Klein Centre, Stockholm, Sweden; Abramowicz, Halina, School of Physics, The University of Sydney, Sydney, Australia; Abreu, Henso, University of Sussex, Brighton, United KingdomThis paper reports searches for heavy resonances decaying into ZZ or ZW using data from proton-proton collisions at a centre-of-mass energy of s=13 TeV. The data, corresponding to an integrated luminosity of 36.1 fb−1, were recorded with the ATLAS detector in 2015 and 2016 at the Large Hadron Collider. The searches are performed in final states in which one Z boson decays into either a pair of light charged leptons (electrons and muons) or a pair of neutrinos, and the associated W boson or the other Z boson decays hadronically. No evidence of the production of heavy resonances is observed. Upper bounds on the production cross sections of heavy resonances times their decay branching ratios to ZZ or ZW are derived in the mass range 300-5000GeV within the context of Standard Model extensions with additional Higgs bosons, a heavy vector triplet or warped extra dimensions. Production through gluon-gluon fusion, Drell-Yan or vector-boson fusion are considered, depending on the assumed model.[Figure not available: see fulltext.]. © 2025 Elsevier B.V., All rights reserved.Publication Open Access Search for heavy resonances decaying into a W or Z boson and a Higgs boson in final states with leptons and b-jets in 36 fb−1 of √s=13 TeV pp collisions with the ATLAS detector(Springer Verlag, 2018) Aaboud, M.; Aad, Georges; Abbott, Brad K.; Abdinov, O. B.; Abeloos, Baptiste; Abidi, Syed Hani; AbouZeid, O. S.; Abraham, Nicola L.; Abramowicz, Halina; Abreu, Henso; Aaboud, M., Faculté des Sciences Aïn Chock, Casablanca, Morocco; Aad, Georges, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom; Abbott, Brad K., Faculty of Science, Okayama University, Okayama, Japan; Abdinov, O. B., Azerbaijan National Academy of Sciences, Baku, Azerbaijan; Abeloos, Baptiste, Center for High Energy Physics, University of Oregon, Eugene, United States; Abidi, Syed Hani, Graduate School of Science and Technology, Tokyo Metropolitan University, Hachioji, Japan; AbouZeid, O. S., Faculty of Science, Université Mohammed Premier Oujda, Oujda, Morocco; Abraham, Nicola L., Oskar Klein Centre, Stockholm, Sweden; Abramowicz, Halina, School of Physics, The University of Sydney, Sydney, Australia; Abreu, Henso, University of Sussex, Brighton, United KingdomA search is conducted for new resonances decaying into a W or Z boson and a 125 GeV Higgs boson in the νν¯ bb¯ , ℓ±νbb¯ , and ℓ+ℓ−bb¯ final states, where ℓ± = e± or μ±, in pp collisions at s=13 TeV. The data used correspond to a total integrated luminosity of 36.1 fb−1 collected with the ATLAS detector at the Large Hadron Collider during the 2015 and 2016 data-taking periods. The search is conducted by examining the reconstructed invariant or transverse mass distributions of W h and Zh candidates for evidence of a localised excess in the mass range of 220 GeV up to 5 TeV. No significant excess is observed and the results are interpreted in terms of constraints on the production cross-section times branching fraction of heavy W′ and Z′ resonances in heavy-vector-triplet models and the CP-odd scalar boson A in two-Higgs-doublet models. Upper limits are placed at the 95% confidence level and range between 9.0 × 10−4 pb and 7.3 × 10−1 pb depending on the model and mass of the resonance.[Figure not available: see fulltext.]. © 2025 Elsevier B.V., All rights reserved.Publication Metadata only Search for Higgs boson decays to beyond-the-Standard-Model light bosons in four-lepton events with the ATLAS detector at √s=13 TeV(Springer Verlag, 2018) Aaboud, M.; Aad, Georges; Abbott, Brad K.; Abdinov, O. B.; Abeloos, Baptiste; Abidi, Syed Hani; AbouZeid, O. S.; Abraham, Nicola L.; Abramowicz, Halina; Abreu, Henso; Aaboud, M., Faculté des Sciences Aïn Chock, Casablanca, Morocco; Aad, Georges, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom; Abbott, Brad K., Faculty of Science, Okayama University, Okayama, Japan; Abdinov, O. B., Azerbaijan National Academy of Sciences, Baku, Azerbaijan; Abeloos, Baptiste, Center for High Energy Physics, University of Oregon, Eugene, United States; Abidi, Syed Hani, Graduate School of Science and Technology, Tokyo Metropolitan University, Hachioji, Japan; AbouZeid, O. S., Faculty of Science, Université Mohammed Premier Oujda, Oujda, Morocco; Abraham, Nicola L., Oskar Klein Centre, Stockholm, Sweden; Abramowicz, Halina, School of Physics, The University of Sydney, Sydney, Australia; Abreu, Henso, University of Sussex, Brighton, United KingdomA search is conducted for a beyond-the-Standard-Model boson using events where a Higgs boson with mass 125 GeV decays to four leptons (ℓ = e or μ). This decay is presumed to occur via an intermediate state which contains one or two on-shell, promptly decaying bosons: H → ZX/XX → 4ℓ, where X is a new vector boson Zd or pseudoscalar a with mass between 1 and 60 GeV. The search uses pp collision data collected with the ATLAS detector at the LHC with an integrated luminosity of 36.1 fb−1 at a centre-of-mass energy s=13 TeV. No significant excess of events above Standard Model background predictions is observed, therefore, upper limits at 95% confidence level are set on modelindependent fiducial cross-sections, and on the Higgs boson decay branching ratios to vector and pseudoscalar bosons in two benchmark models.[Figure not available: see fulltext.]. © 2025 Elsevier B.V., All rights reserved.Publication Open Access Search for pair production of up-type vector-like quarks and for four-top-quark events in final states with multiple b-jets with the ATLAS detector(Springer Verlag, 2018) Aaboud, M.; Aad, Georges; Abbott, Brad K.; Abdinov, O. B.; Abeloos, Baptiste; Abidi, Syed Hani; AbouZeid, O. S.; Abraham, Nicola L.; Abramowicz, Halina; Abreu, Henso; Aaboud, M., Faculté des Sciences Aïn Chock, Casablanca, Morocco; Aad, Georges, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom; Abbott, Brad K., Faculty of Science, Okayama University, Okayama, Japan; Abdinov, O. B., Azerbaijan National Academy of Sciences, Baku, Azerbaijan; Abeloos, Baptiste, Center for High Energy Physics, University of Oregon, Eugene, United States; Abidi, Syed Hani, Graduate School of Science and Technology, Tokyo Metropolitan University, Hachioji, Japan; AbouZeid, O. S., Faculty of Science, Université Mohammed Premier Oujda, Oujda, Morocco; Abraham, Nicola L., Oskar Klein Centre, Stockholm, Sweden; Abramowicz, Halina, School of Physics, The University of Sydney, Sydney, Australia; Abreu, Henso, University of Sussex, Brighton, United KingdomA search for pair production of up-type vector-like quarks (T) with a significant branching ratio into a top quark and either a Standard Model Higgs boson or a Z boson is presented. The same analysis is also used to search for four-top-quark production in several new physics scenarios. The search is based on a dataset of pp collisions at s=13 TeV recorded in 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider and corresponds to an integrated luminosity of 36.1 fb-1. Data are analysed in the lepton+jets final state, characterised by an isolated electron or muon with high transverse momentum, large missing transverse momentum and multiple jets, as well as the jets + ETmiss final state, characterised by multiple jets and large missing transverse momentum. The search exploits the high multiplicity of jets identified as originating from b-quarks, and the presence of boosted, hadronically decaying top quarks and Higgs bosons reconstructed as large-radius jets, characteristic of signal events. No significant excess above the Standard Model expectation is observed, and 95% CL upper limits are set on the production cross sections for the different signal processes considered. These cross-section limits are used to derive lower limits on the mass of a vector-like T quark under several branching ratio hypotheses assuming contributions from T ? W b, Zt, Ht decays. The 95% CL observed lower limits on the T quark mass range between 0.99 TeV and 1.43 TeV for all possible values of the branching ratios into the three decay modes considered, significantly extending the reach beyond that of previous searches. Additionally, upper limits on anomalous four-top-quark production are set in the context of an effective field theory model, as well as in an universal extra dimensions model.[Figure not available: see fulltext.]. © 2025 Elsevier B.V., All rights reserved.