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Publication Metadata only Search for squarks and gluinos in final states with jets and missing transverse momentum at √s = 13 TeV with the ATLAS detector(Springer, 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, Aix Marseille Université, 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., 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 for squarks and gluinos in final states containing hadronic jets, missing transverse momentum but no electrons or muons is presented. The data were recorded in 2015 by the ATLAS experiment in √s = 13 TeV proton-proton collisions at the Large Hadron Collider. No excess above the Standard Model background expectation was observed in 3.2 fb−1 of analyzed data. Results are interpreted within simplified models that assume R-parity is conserved and the neutralino is the lightest supersymmetric particle. An exclusion limit at the 95 % confidence level on the mass of the gluino is set at 1.51 TeV for a simplified model incorporating only a gluino octet and the lightest neutralino, assuming the lightest neutralino is massless. For a simplified model involving the strong production of mass-degenerate first- and second-generation squarks, squark masses below 1.03 TeV are excluded for a massless lightest neutralino. These limits substantially extend the region of supersymmetric parameter space excluded by previous measurements with the ATLAS detector. © 2019 Elsevier B.V., All rights reserved.Publication Metadata only Measurement of event-shape observables in Z → ℓ+ℓ− events in pp collisions at √ s = 7 TeV with the ATLAS detector at the LHC(Springer New York LLC barbara.b.bertram@gsk.com, 2016) Aad, Georges; Abbott, Brad K.; Abdallah, Jalal Mohamad; Abdinov, O. B.; Abeloos, Baptiste; Aben, R.; Abolins, Maris A.; AbouZeid, O. S.; Abraham, Nicola L.; Abramowicz, Halina; 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, Institute of Physics, Academia Sinica, Institute Of Physics, Taipei, Taiwan; 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; Abolins, Maris A., Department of Physics and Astronomy, Michigan State University, East Lansing, United States; 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, IsraelEvent-shape observables measured using charged particles in inclusive Z-boson events are presented, using the electron and muon decay modes of the Z bosons. The measurements are based on an integrated luminosity of 1.1 fb−1 of proton-proton collisions recorded by the ATLAS detector at theLHCat a centre-of-mass energy √ s = 7TeV.Chargedparticle distributions, excluding the lepton-antilepton pair from the Z-boson decay, are measured in different ranges of transverse momentum of the Z boson. Distributions include multiplicity, scalar sum of transverse momenta, beam thrust, transverse thrust, spherocity, and F-parameter, which are in particular sensitive to properties of the underlying event at small values of the Z-boson transverse momentum. The measured observables are compared with predictions from Pythia 8, Sherpa, and Herwig7. Typically, all three Monte Carlo generators provide predictions that are in better agreement with the data at high Z-boson transverse momenta than at low Z-boson transverse momenta, and for the observables that are less sensitive to the number of charged particles in the event. © 2017 Elsevier B.V., All rights reserved.Publication Metadata only Charged-particle distributions in pp interactions at √s = 8 TeV measured with the ATLAS detector(Springer Science and Business Media Deutschland GmbH, 2016) Aad, Georges; Abbott, Brad K.; Abdallah, Jalal Mohamad; Abdinov, O. B.; Abeloos, Baptiste; Aben, R.; Abolins, Maris A.; AbouZeid, O. S.; Abraham, Nicola L.; Abramowicz, Halina; Aad, Georges, Centre de Physique des Particules de Marseille, Marseille, France; Abbott, Brad K., The University of Oklahoma, Norman, United States; Abdallah, Jalal Mohamad, Academia Sinica, Institute Of Physics, Taipei, Taiwan; 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; Abolins, Maris A., Department of Physics and Astronomy, Michigan State University, East Lansing, United States; 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, IsraelThis paper presents measurements of distributions of charged particles which are produced in proton-proton collisions at a centre-of-mass energy of √s = 8 TeV and recorded by the ATLAS detector at the LHC. A special dataset recorded in 2012 with a small number of interactions per beam crossing (below 0.004) and corresponding to an integrated luminosity of 160 µb-1 was used. A minimum-bias trigger was utilised to select a data sample of more than 9 million collision events. The multiplicity, pseudorapidity, and transverse momentum distributions of charged particles are shown in different regions of kinematics and chargedparticle multiplicity, including measurements of final states at high multiplicity. The results are corrected for detector effects and are compared to the predictions of various Monte Carlo event generator models which simulate the full hadronic final state. © 2024 Elsevier B.V., All rights reserved.Publication Metadata only Search for scalar leptoquarks in pp collisions at √S = 13TeV with the ATLAS experiment(Institute of Physics, 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., 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; 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, IsraelAn inclusive search for a new-physics signature of lepton-jet resonances has been performed by the ATLAS experiment. Scalar leptoquarks, pair-produced in pp collisions at s √S13 TeV at the large hadron collider, have been considered. An integrated luminosity of 3.2 fb−1, corresponding to the full 2015 dataset was used. First (second) generation leptoquarks were sought in events with two electrons (muons) and two or more jets. The observed event yield in each channel is consistent with Standard Model background expectations. The observed (expected) lower limits on the leptoquark mass at 95% confidence level are 1100 and 1050 GeV (1160 and 1040 GeV) for first and second generation leptoquarks, respectively, assuming a branching ratio into a charged lepton and a quark of 100%. Upper limits on the aforementioned branching ratio are also given as a function of leptoquark mass. Compared with the results of earlier ATLAS searches, the sensitivity is increased for leptoquark masses above 860 GeV, and the observed exclusion limits confirm and extend the published results. © 2022 Elsevier B.V., All rights reserved.Publication Metadata only Measurement of the total cross section from elastic scattering in pp collisions at √s=8 TeV with the ATLAS detector(Elsevier B.V., 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, Aix Marseille Université, 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 measurement of the total pp cross section at the LHC at s=8 TeV is presented. An integrated luminosity of 500 μb−1 was accumulated in a special run with high-β⋆ beam optics to measure the differential elastic cross section as a function of the Mandelstam momentum transfer variable t. The measurement is performed with the ALFA sub-detector of ATLAS. Using a fit to the differential elastic cross section in the −t range from 0.014 GeV2 to 0.1 GeV2 to extrapolate t→0, the total cross section, σtot(pp→X), is measured via the optical theorem to be σtot(pp→X)=96.07±0.18(stat.)±0.85(exp.)±0.31(extr.)mb, where the first error is statistical, the second accounts for all experimental systematic uncertainties and the last is related to uncertainties in the extrapolation t→0. In addition, the slope of the exponential function describing the elastic cross section at small t is determined to be B=19.74±0.05(stat.)±0.23(syst.)GeV−2. © 2019 Elsevier B.V., All rights reserved.Publication Metadata only Search for strong gravity in multijet final states produced in pp collisions at √s = 13 TeV using the ATLAS detector at the LHC(Springer Verlag service@springer.de, 2016) The Atlas Collaboration; Aad, Georges; Abbott, Brad K.; Abdallah, Jalal Mohamad; Abdinov, O. B.; Abeloos, Baptiste; Aben, R.; Abolins, Maris A.; AbouZeid, O. S.; Abramowicz, Halina; The Atlas Collaboration, null, Organisation Européenne pour la Recherche Nucléaire, Geneva, Switzerland; Aad, Georges, Aix Marseille Université, Marseille, France; Abbott, Brad K., Homer L. Dodge Department of Physics and Astronomy, The University of Oklahoma, Norman, United States; Abdallah, Jalal Mohamad, Academia Sinica, Institute Of Physics, Taipei, Taiwan; 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; Abolins, Maris A., Department of Physics and Astronomy, Michigan State University, East Lansing, United States; AbouZeid, O. S., Department of Physics, University of Toronto, Toronto, Canada; Abramowicz, Halina, Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv-Yafo, IsraelAbstract: A search is conducted for new physics in multijet final states using 3.6 inverse femtobarns of data from proton-proton collisions at (Formula presented.) TeV taken at the CERN Large Hadron Collider with the ATLAS detector. Events are selected containing at least three jets with scalar sum of jet transverse momenta (HT) greater than 1 TeV. No excess is seen at large HTand limits are presented on new physics: models which produce final states containing at least three jets and having cross sections larger than 1.6 fb with HT> 5.8 TeV are excluded. Limits are also given in terms of new physics models of strong gravity that hypothesize additional space-time dimensions.[Figure not available: see fulltext.] © 2019 Elsevier B.V., All rights reserved.Publication Metadata only Search for new phenomena with photon+jet events in proton-proton collisions at √s = 13 TeV with the ATLAS detector(Springer Verlag service@springer.de, 2016) The Atlas Collaboration; Aad, Georges; Abbott, Brad K.; Abdallah, Jalal Mohamad; Abdinov, O. B.; Abeloos, Baptiste; Aben, R.; Abolins, Maris A.; AbouZeid, O. S.; Abramowicz, Halina; The Atlas Collaboration, null, Organisation Européenne pour la Recherche Nucléaire, Geneva, Switzerland; Aad, Georges, Aix Marseille Université, Marseille, France; Abbott, Brad K., Homer L. Dodge Department of Physics and Astronomy, The University of Oklahoma, Norman, United States; Abdallah, Jalal Mohamad, Academia Sinica, Institute Of Physics, Taipei, Taiwan; 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; Abolins, Maris A., Department of Physics and Astronomy, Michigan State University, East Lansing, United States; AbouZeid, O. S., Santa Cruz Institute for Particle Physics, Santa Cruz, United States; Abramowicz, Halina, Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv-Yafo, IsraelAbstract: A search is performed for the production of high-mass resonances decaying into a photon and a jet in 3.2 fb−1of proton-proton collisions at a centre-of-mass energy of (Formula presented.) TeV collected by the ATLAS detector at the Large Hadron Collider. Selected events have an isolated photon and a jet, each with transverse momentum above 150 GeV. No significant deviation of the γ+jet invariant mass distribution from the background-only hypothesis is found. Limits are set at 95% confidence level on the cross sections of generic Gaussian-shaped signals and of a few benchmark phenomena beyond the Standard Model: excited quarks with vector-like couplings to the Standard Model particles, and non-thermal quantum black holes in two models of extra spatial dimensions. The minimum excluded visible cross sections for Gaussian-shaped resonances with width-to-mass ratios of 2% decrease from about 6 fb for a mass of 1.5 TeV to about 0.8 fb for a mass of 5 TeV. The minimum excluded visible cross sections for Gaussian-shaped resonances with width-to-mass ratios of 15% decrease from about 50 fb for a mass of 1.5 TeV to about 1.0 fb for a mass of 5 TeV. Excited quarks are excluded below masses of 4.4 TeV, and non-thermal quantum black holes are excluded below masses of 3.8 (6.2) TeV for Randall-Sundrum (Arkani-Hamed-Dimopoulous-Dvali) models with one (six) extra dimensions.[Figure not available: see fulltext.] © 2019 Elsevier B.V., All rights reserved.Publication Metadata only Measurement of the ZZ production cross section in pp collisions at √s = 13 TeV with the ATLAS detector(American Physical Society revtex@aps.org, 2016) Aad, Georges; Abbott, Brad K.; Abdallah, Jalal Mohamad; Abdinov, O. B.; Abeloos, Baptiste; Aben, R.; Abolins, Maris A.; AbouZeid, O. S.; Abramowicz, Halina; Abreu, Henso; Aad, Georges, Aix Marseille Université, Marseille, France; Abbott, Brad K., Homer L. Dodge Department of Physics and Astronomy, The University of Oklahoma, Norman, United States; Abdallah, Jalal Mohamad, Academia Sinica, Institute Of Physics, Taipei, Taiwan; 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; Abolins, Maris A., Department of Physics and Astronomy, Michigan State University, East Lansing, United States; AbouZeid, O. S., Santa Cruz Institute for Particle Physics, Santa Cruz, United States; Abramowicz, Halina, Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv-Yafo, Israel; Abreu, Henso, Department of Physics, Technion - Israel Institute of Technology, Haifa, IsraelThe ZZ production cross section in proton-proton collisions at 13 TeV center-of-mass energy is measured using 3.2 fb-1 of data recorded with the ATLAS detector at the Large Hadron Collider. The considered Z boson candidates decay to an electron or muon pair of mass 66-116 GeV. The cross section is measured in a fiducial phase space reflecting the detector acceptance. It is also extrapolated to a total phase space for Z bosons in the same mass range and of all decay modes, giving 16.7-2.0+2.2(stat)+0.9-0.7(syst)+1.0-0.7(lumi) pb. The results agree with standard model predictions. © 2019 Elsevier B.V., All rights reserved.Publication Metadata only Search for new phenomena in dijet mass and angular distributions from pp collisions at √s=13 TeV with the ATLAS detector(Elsevier B.V., 2016) Aad, Georges; Abbott, Brad K.; Abdallah, Jalal Mohamad; Abdinov, O. B.; Abeloos, Baptiste; Aben, R.; Abolins, Maris A.; AbouZeid, O. S.; Abramowicz, Halina; Abreu, Henso; 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, Academia Sinica, Institute Of Physics, Taipei, Taiwan; 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; Abolins, Maris A., Department of Physics and Astronomy, Michigan State University, East Lansing, United States; AbouZeid, O. S., Department of Physics, University of Toronto, Toronto, Canada; Abramowicz, Halina, Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv-Yafo, Israel; Abreu, Henso, Department of Physics, Technion - Israel Institute of Technology, Haifa, IsraelThis Letter describes a model-agnostic search for pairs of jets (dijets) produced by resonant and non-resonant phenomena beyond the Standard Model in 3.6 fb−1 of proton–proton collisions with a centre-of-mass energy of s=13 TeV recorded by the ATLAS detector at the Large Hadron Collider. The distribution of the invariant mass of the two leading jets is examined for local excesses above a data-derived estimate of the smoothly falling prediction of the Standard Model. The data are also compared to a Monte Carlo simulation of Standard Model angular distributions derived from the rapidity of the two jets. No evidence of anomalous phenomena is observed in the data, which are used to exclude, at 95% CL, quantum black holes with threshold masses below 8.3 TeV, 8.1 TeV, or 5.1 TeV in three different benchmark scenarios, resonance masses below 5.2 TeV for excited quarks, 2.6 TeV in a W′ model, a range of masses starting from mZ′ =1.5 TeV and couplings from gq=0.2 in a Z′ model, and contact interactions with a compositeness scale below 12.0 TeV and 17.5 TeV respectively for destructive and constructive interference between the new interaction and QCD processes. These results significantly extend the ATLAS limits obtained from 8 TeV data. Gaussian-shaped contributions to the mass distribution are also excluded if the effective cross-section exceeds values ranging from approximately 50–300 fb for masses below 2 TeV to 2–20 fb for masses above 4 TeV. © 2019 Elsevier B.V., All rights reserved.Publication Metadata only Search for supersymmetry at √s= 13 TeV in final states with jets and two same-sign leptons or three leptons with the ATLAS detector(Springer New York LLC barbara.b.bertram@gsk.com, 2016) Atlas Collaboration; Aad, Georges; Abbott, Brad K.; Abdallah, Jalal Mohamad; Abdinov, O. B.; Abeloos, Baptiste; Aben, R.; Abolins, Maris A.; AbouZeid, O. S.; Abramowicz, Halina; Atlas Collaboration, null, Organisation Européenne pour la Recherche Nucléaire, Geneva, Switzerland; 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, Academia Sinica, Institute Of Physics, Taipei, Taiwan; 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; Abolins, Maris A., Department of Physics and Astronomy, Michigan State University, East Lansing, United States; AbouZeid, O. S., Santa Cruz Institute for Particle Physics, Santa Cruz, United States; Abramowicz, Halina, Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv-Yafo, IsraelA search for strongly produced supersymmetric particles is conducted using signatures involving multiple energetic jets and either two isolated leptons (e or μ) with the same electric charge or at least three isolated leptons. The search also utilises b-tagged jets, missing transverse momentum and other observables to extend its sensitivity. The analysis uses a data sample of proton–proton collisions at √s= 13 TeV recorded with the ATLAS detector at the Large Hadron Collider in 2015 corresponding to a total integrated luminosity of 3.2 fb-1. No significant excess over the Standard Model expectation is observed. The results are interpreted in several simplified supersymmetric models and extend the exclusion limits from previous searches. In the context of exclusive production and simplified decay modes, gluino masses are excluded at 95 % confidence level up to 1.1–1.3 TeV for light neutralinos (depending on the decay channel), and bottom squark masses are also excluded up to 540 GeV. In the former scenarios, neutralino masses are also excluded up to 550–850 GeV for gluino masses around 1 TeV. © 2019 Elsevier B.V., All rights reserved.