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Publication Open Access Measurements of the Higgs boson production and decay rates and constraints on its couplings from a combined ATLAS and CMS analysis of the LHC pp collision data at √s = 7 and 8 TeV(Springer Science and Business Media Deutschland GmbH, 2016) The Atlas Collaboration; Aad, Georges; Abbott, Brad K.; Abdallah, Jalal Mohamad; Abdinov, O. B.; Abeloos, Baptiste; Aben, R.; AbouZeid, O. S.; Abraham, Nicola L.; Abramowicz, Halina; The Atlas Collaboration, null, Universitatea Transilvania din Brașov, Brasov, Romania, University Politehnica of Bucharest, Bucharest, Romania, Universitatea de Vest din Timișoara, Timisoara, 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,; Aad, Georges, Centre de Physique des Particules de Marseille, Marseille, France; Abbott, Brad K., 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., University of Sussex, Brighton, United Kingdom; Abramowicz, Halina, Tel Aviv University, Tel Aviv-Yafo, IsraelCombined ATLAS and CMS measurements of the Higgs boson production and decay rates, as well as constraints on its couplings to vector bosons and fermions, are presented. The combination is based on the analysis of five production processes, namely gluon fusion, vector boson fusion, and associated production with a W or a Z boson or a pair of top quarks, and of the six decay modes H → ZZ, W W, γγ, ττ, bb, and μμ. All results are reported assuming a value of 125.09 GeV for the Higgs boson mass, the result of the combined measurement by the ATLAS and CMS experiments. The analysis uses the CERN LHC proton-proton collision data recorded by the ATLAS and CMS experiments in 2011 and 2012, corresponding to integrated luminosities per experiment of approximately 5 fb−1 at √s = 7 TeV and 20 fb−1 at √s = 8 TeV. The Higgs boson production and decay rates measured by the two experiments are combined within the context of three generic parameterisations: two based on cross sections and branching fractions, and one on ratios of coupling modifiers. Several interpretations of the measurements with more model-dependent parameterisations are also given. The combined signal yield relative to the Standard Model prediction is measured to be 1.09 ± 0.11. The combined measurements lead to observed significances for the vector boson fusion production process and for the H → ττ decay of 5.4 and 5.5 standard deviations, respectively. The data are consistent with the Standard Model predictions for all parameterisations considered. © 2023 Elsevier B.V., All rights reserved.Publication Open Access Search for the Standard Model Higgs boson produced by vector-boson fusion and decaying to bottom quarks in √s=8 TeV pp collisions with the ATLAS detector(Springer Verlag [email protected], 2016) Aaboud, M.; Aad, Georges; Abbott, Brad K.; Abdallah, Jalal Mohamad; Abdinov, O. B.; Abeloos, Baptiste; Aben, R.; AbouZeid, O. S.; Abraham, Nicola L.; Abramowicz, Halina; 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 Kingdom; Abramowicz, Halina, Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv-Yafo, IsraelA search with the ATLAS detector is presented for the Standard Model Higgs boson produced by vector-boson fusion and decaying to a pair of bottom quarks, using 20.2 fb−1 of LHC proton-proton collision data at s=8 TeV. The signal is searched for as a resonance in the invariant mass distribution of a pair of jets containing b-hadrons in vector-boson-fusion candidate events. The yield is measured to be −0.8 ± 2.3 times the Standard Model cross-section for a Higgs boson mass of 125 GeV. The upper limit on the cross-section times the branching ratio is found to be 4.4 times the Standard Model cross-section at the 95% confidence level, consistent with the expected limit value of 5.4 (5.7) in the background-only (Standard Model production) hypothesis.[Figure not available: see fulltext.] © 2016 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 Searches for the Zγ decay mode of the Higgs boson and for new high-mass resonances in pp collisions 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, IsraelThis article presents searches for the Zγ decay of the Higgs boson and for narrow high-mass resonances decaying to Zγ, exploiting Z boson decays to pairs of electrons or muons. The data analysis uses 36.1 fb−1 of pp collisions at s=13 recorded by the ATLAS detector at the CERN Large Hadron Collider. The data are found to be consistent with the expected Standard Model background. The observed (expected — assuming Standard Model pp → H → Zγ production and decay) upper limit on the production cross section times the branching ratio for pp → H → Zγ is 6.6. (5.2) times the Standard Model prediction at the 95% confidence level for a Higgs boson mass of 125.09 GeV. In addition, upper limits are set on the production cross section times the branching ratio as a function of the mass of a narrow resonance between 250 GeV and 2.4 TeV, assuming spin-0 resonances produced via gluon-gluon fusion, and spin-2 resonances produced via gluon-gluon or quark-antiquark initial states. For high-mass spin-0 resonances, the observed (expected) limits vary between 88 fb (61 fb) and 2.8 fb (2.7 fb) for the mass range from 250 GeV to 2.4 TeV at the 95% confidence level. © 2025 Elsevier B.V., All rights reserved.Publication Open Access Search for top quark decays t → qH, with H → γγ, in √s=13 TeV pp collisions using 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, IsraelThis article presents a search for flavour-changing neutral currents in the decay of a top quark into an up-type (q = c, u) quark and a Higgs boson, where the Higgs boson decays into two photons. The proton-proton collision data set analysed amounts to 36.1 fb−1 at s=13 TeV collected by the ATLAS experiment at the LHC. Top quark pair events are searched for, where one top quark decays into qH and the other decays into bW. Both the hadronic and leptonic decay modes of the W boson are used. No significant excess is observed and an upper limit is set on the t → cH branching ratio of 2.2 × 10−3 at the 95% confidence level, while the expected limit in the absence of signal is 1.6 × 10−3. The corresponding limit on the tcH coupling is 0.090 at the 95% confidence level. The observed upper limit on the t → uH branching ratio is 2.4 × 10−3.[Figure not available: see fulltext.]. © 2025 Elsevier B.V., All rights reserved.Publication Open Access Measurement of inclusive and differential cross sections in the H → ZZ * → 4ℓ decay channel in pp collisions 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, IsraelInclusive and differential fiducial cross sections of Higgs boson production in proton-proton collisions are measured in the H → ZZ* → 4ℓ decay channel. The proton-proton collision data were produced at the Large Hadron Collider at a centre-of-mass energy of 13 TeV and recorded by the ATLAS detector in 2015 and 2016, corresponding to an integrated luminosity of 36.1 fb−1. The inclusive fiducial cross section in the H → ZZ* → 4ℓ decay channel is measured to be 3.62 ± 0.50(stat)− 0.20 + 0.25 (sys) fb, in agreement with the Standard Model prediction of 2.91 ± 0.13 fb. The cross section is also extrapolated to the total phase space including all Standard Model Higgs boson decays. Several differential fiducial cross sections are measured for observables sensitive to the Higgs boson production and decay, including kinematic distributions of jets produced in association with the Higgs boson. Good agreement is found between data and Standard Model predictions. The results are used to put constraints on anomalous Higgs boson interactions with Standard Model particles, using the pseudo-observable extension to the kappa-framework.[Figure not available: see fulltext.]. © 2025 Elsevier B.V., All rights reserved.Publication Open Access Evidence for the H → bb decay with the ATLAS detector(Springer Science and Business Media Deutschland GmbH, 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 the decay of the Standard Model Higgs boson into a bb pair when produced in association with a W or Z boson is performed with the ATLAS detector. The analysed data, corresponding to an integrated luminosity of 36.1 fb-1, were collected in proton-proton collisions in Run 2 of the Large Hadron Collider at a centre-of-mass energy of 13TeV. Final states containing zero, one and two charged leptons (electrons or muons) are considered, targeting the decays Z → νν, W → ℓν and Z → ℓℓ. For a Higgs boson mass of 125 GeV, an excess of events over the expected background from other Standard Model processes is found with an observed significance of 3.5 standard deviations, compared to an expectation of 3.0 standard deviations. This excess provides evidence for the Higgs boson decay into b-quarks and for its production in association with a vector boson. The combination of this result with that of the Run 1 analysis yields a ratio of the measured signal events to the Standard Model expectation equal to 0.90 ± 0.18(stat.)+0.21 -0.19(syst.). Assuming the Standard Model production cross-section, the results are consistent with the value of the Yukawa coupling to b-quarks in the Standard Model. © 2025 Elsevier B.V., All rights reserved.Publication Open Access Search for exclusive Higgs and Z boson decays to ϕγ and ργ 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 the exclusive decays of the Higgs and Z bosons to a ϕ or ρ meson and a photon is performed with a pp collision data sample corresponding to an integrated luminosity of up to 35.6 fb−1 collected at s=13 TeV with the ATLAS detector at the CERN Large Hadron Collider. These decays have been suggested as a probe of the Higgs boson couplings to light quarks. No significant excess of events is observed above the background, as expected from the Standard Model. Upper limits at 95% confidence level were obtained on the branching fractions of the Higgs boson decays to ϕγ and ργ of 4.8 × 10−4 and 8.8 × 10−4, respectively. The corresponding 95% confidence level upper limits for the Z boson decays are 0.9 × 10−6 and 25 × 10−6 for ϕγ and ργ, respectively.[Figure not available: see fulltext.]. © 2025 Elsevier B.V., All rights reserved.Publication Open Access Search for charged Higgs bosons decaying via H ± → τ ± ντ in the τ+jets and τ+lepton final states with 36 fb−1 of pp collision data recorded at √s=13 TeV with the ATLAS experiment(Springer Verlag, 2018) Aaboud, M.; Aad, Georges; Abbott, Brad K.; Abdinov, O. B.; Abeloos, Baptiste; Abhayasinghe, D. K.; Abidi, Syed Hani; AbouZeid, O. S.; Abraham, Nicola L.; Abramowicz, Halina; Aaboud, M., National Energy Center of Nuclear Science and Technology, Rabat, Morocco; Aad, Georges, Johannes Gutenberg-Universität Mainz, Mainz, Germany; Abbott, Brad K., The Ohio State University, Columbus, United States; Abdinov, O. B., Azerbaijan National Academy of Sciences, Baku, Azerbaijan; Abeloos, Baptiste, Joint Laboratory of Optics, Olomouc, Czech Republic; Abhayasinghe, D. K., Department of Experimental Particle Physics, Univerza v Ljubljani, Ljubljana, Slovenia; Abidi, Syed Hani, Graduate School of Science and Technology, Tokyo Metropolitan University, Hachioji, Japan; AbouZeid, O. S., Université Clermont Auvergne, Clermont-Ferrand, France; Abraham, Nicola L., SLAC National Accelerator Laboratory, Menlo Park, United States; Abramowicz, Halina, Elevter Andronikashvili Institute of Physics, Tbilisi, GeorgiaCharged Higgs bosons produced either in top-quark decays or in association with a top-quark, subsequently decaying via H± → τ±ντ, are searched for in 36.1 fb−1 of proton-proton collision data at s=13 TeV recorded with the ATLAS detector. Depending on whether the top-quark produced together with H± decays hadronically or leptonically, the search targets τ+jets and τ+lepton final states, in both cases with a hadronically decaying τ-lepton. No evidence of a charged Higgs boson is found. For the mass range of mH± = 90–2000 GeV, upper limits at the 95% confidence level are set on the production cross-section of the charged Higgs boson times the branching fraction ℬ (H±→ τ±ντ) in the range 4.2–0.0025 pb. In the mass range 90–160 GeV, assuming the Standard Model cross-section for tt¯ production, this corresponds to upper limits between 0.25% and 0.031% for the branching fraction ℬ(t→bH±)×ℬ(H±→τ±ντ).[Figure not available: see fulltext.] © 2025 Elsevier B.V., All rights reserved.Publication Open Access Search for the Higgs boson produced in association with a vector boson and decaying into two spin-zero particles in the H → aa → 4b channel 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; Abhayasinghe, D. K.; Abidi, Syed Hani; AbouZeid, O. S.; Abraham, Nicola L.; Abramowicz, Halina; Aaboud, M., National Energy Center of Nuclear Science and Technology, Rabat, Morocco; Aad, Georges, Johannes Gutenberg-Universität Mainz, Mainz, Germany; Abbott, Brad K., The Ohio State University, Columbus, United States; Abdinov, O. B., Azerbaijan National Academy of Sciences, Baku, Azerbaijan; Abeloos, Baptiste, Joint Laboratory of Optics, Olomouc, Czech Republic; Abhayasinghe, D. K., Department of Experimental Particle Physics, Univerza v Ljubljani, Ljubljana, Slovenia; Abidi, Syed Hani, Graduate School of Science and Technology, Tokyo Metropolitan University, Hachioji, Japan; AbouZeid, O. S., Université Clermont Auvergne, Clermont-Ferrand, France; Abraham, Nicola L., SLAC National Accelerator Laboratory, Menlo Park, United States; Abramowicz, Halina, Elevter Andronikashvili Institute of Physics, Tbilisi, GeorgiaA search for exotic decays of the Higgs boson into a pair of spin-zero particles, H → aa, where the a-boson decay sin to b-quarks promptly or with a mean proper lifetime cτa up to 6 mm and has a mass in the range of 20–60 GeV, is presented. The search is performed in events where the Higgs boson is produced in association with a W or Z boson, giving rise to a signature of one or two charged leptons (electrons or muons) and multiple jets from b-quark decays. The analysis is based on the dataset of proton-proton collisions at s=13 TeV recorded in 2015 and 2016 by the ATLAS detector at the CERN Large Hadron Collider, corresponding to an integrated luminosity of 36.1 fb−1. No significant excess of events above the Standard Model background prediction is observed, and 95% confidence-level upper limits are derived for the production cross-sections for pp → WH, ZH and their combination, times the branching ratio of the decay chain H → aa → 4b. For a-bosons which decay promptly, the upper limit on the combination of cross-sections for WH and ZH times the branching ratio of H → aa → 4b ranges from 3.0 pb for ma = 20 GeV to 1.3 pb for ma = 60 GeV, assuming that the ratio of WH to ZH cross-sections follows the Standard Model prediction. For a-bosons with longer proper lifetimes, the most stringent limits are 1.8 pb and 0.68 pb, respectively, at cτa ∼ 0.4 mm.[Figure not available: see fulltext.]. © 2025 Elsevier B.V., All rights reserved.