https://doi.org/10.1140/epjc/s10052-019-6962-6
Regular Article - Experimental Physics
Search for long-lived neutral particles in pp collisions at 
that decay into displaced hadronic jets in the ATLAS calorimeter
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Department of Physics, University of Adelaide, Adelaide, Australia
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Physics Department, SUNY Albany, Albany, NY, USA
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Department of Physics, University of Alberta, Edmonton, AB, Canada
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Department of Physics, Ankara University, Ankara, Canada
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Istanbul Aydin University, Istanbul, Canada
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Division of Physics, TOBB University of Economics and Technology, Ankara, Turkey
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LAPP, Université Grenoble Alpes, Université Savoie Mont Blanc, CNRS/IN2P3, Annecy, France
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High Energy Physics Division, Argonne National Laboratory, Argonne, IL, USA
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Department of Physics, University of Arizona, Tucson, AZ, USA
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Department of Physics, University of Texas at Arlington, Arlington, TX, USA
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Physics Department, National and Kapodistrian University of Athens, Athens, Greece
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Physics Department, National Technical University of Athens, Zografou, Greece
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Department of Physics, University of Texas at Austin, Austin, TX, USA
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Bahcesehir University, Faculty of Engineering and Natural Sciences, Istanbul, USA
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Istanbul Bilgi University, Faculty of Engineering and Natural Sciences, Istanbul, USA
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Department of Physics, Bogazici University, Istanbul, USA
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Department of Physics Engineering, Gaziantep University, Gaziantep, Turkey
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Institute of Physics, Azerbaijan Academy of Sciences, Baku, Azerbaijan
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Institut de Física d’Altes Energies (IFAE), Barcelona Institute of Science and Technology, Barcelona, Spain
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Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, Spain
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Physics Department, Tsinghua University, Beijing, Spain
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Department of Physics, Nanjing University, Nanjing, Spain
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University of Chinese Academy of Science (UCAS), Beijing, China
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Institute of Physics, University of Belgrade, Belgrade, Serbia
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Department for Physics and Technology, University of Bergen, Bergen, Norway
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Physics Division, Lawrence Berkeley National Laboratory and University of California, Berkeley, CA, USA
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Institut für Physik, Humboldt Universität zu Berlin, Berlin, Germany
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Albert Einstein Center for Fundamental Physics and Laboratory for High Energy Physics, University of Bern, Bern, Switzerland
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School of Physics and Astronomy, University of Birmingham, Birmingham, UK
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Facultad de Ciencias y Centro de Investigaciónes, Universidad Antonio Nariño, Bogota, Colombia
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Dipartimento di Fisica, INFN Bologna and Universita’ di Bologna, Bologna, Italy
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INFN Sezione di Bologna, Bologna, Italy
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Physikalisches Institut, Universität Bonn, Bonn, Germany
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Department of Physics, Boston University, Boston, MA, USA
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Department of Physics, Brandeis University, Waltham, MA, USA
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Transilvania University of Brasov, Brasov, USA
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Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest, USA
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Department of Physics, Alexandru Ioan Cuza University of Iasi, Iasi, USA
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National Institute for Research and Development of Isotopic and Molecular Technologies, Physics Department, Cluj-Napoca, USA
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University Politehnica Bucharest, Bucharest, USA
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West University in Timisoara, Timisoara, Romania
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Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Romania
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Department of Subnuclear Physics, Institute of Experimental Physics of the Slovak Academy of Sciences, Kosice, Slovak Republic
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Physics Department, Brookhaven National Laboratory, Upton, NY, USA
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Departamento de Física, Universidad de Buenos Aires, Buenos Aires, Argentina
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Cavendish Laboratory, University of Cambridge, Cambridge, UK
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Department of Physics, University of Cape Town, Cape Town, UK
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Department of Mechanical Engineering Science, University of Johannesburg, Johannesburg, UK
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School of Physics, University of the Witwatersrand, Johannesburg, South Africa
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Department of Physics, Carleton University, Ottawa, ON, Canada
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Faculté des Sciences Ain Chock, Réseau Universitaire de Physique des Hautes Energies - Université Hassan II, Casablanca, Canada
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Centre National de l’Energie des Sciences Techniques Nucleaires (CNESTEN), Rabat, Canada
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Faculté des Sciences Semlalia, Université Cadi Ayyad, LPHEA-Marrakech, Canada
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Faculté des Sciences, Université Mohamed Premier and LPTPM, Oujda, Canada
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Faculté des sciences, Université Mohammed V, Rabat, Morocco
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CERN, Geneva, Switzerland
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Enrico Fermi Institute, University of Chicago, Chicago, IL, USA
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LPC, Université Clermont Auvergne, CNRS/IN2P3, Clermont-Ferrand, France
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Nevis Laboratory, Columbia University, Irvington, NY, USA
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Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
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Dipartimento di Fisica, Università della Calabria, Rende, Denmark
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INFN Gruppo Collegato di Cosenza, Laboratori Nazionali di Frascati, Italy
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Physics Department, Southern Methodist University, Dallas, TX, USA
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Physics Department, University of Texas at Dallas, Richardson, TX, USA
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National Centre for Scientific Research “Demokritos”, Agia Paraskevi, Greece
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Department of Physics, Stockholm University, Greece
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Oskar Klein Centre, Stockholm, Sweden
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Deutsches Elektronen-Synchrotron DESY, Hamburg and Zeuthen, Germany
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Lehrstuhl für Experimentelle Physik IV, Technische Universität Dortmund, Dortmund, Germany
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Institut für Kern- und Teilchenphysik, Technische Universität Dresden, Dresden, Germany
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Department of Physics, Duke University, Durham, NC, USA
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SUPA - School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
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INFN e Laboratori Nazionali di Frascati, Frascati, Italy
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Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
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II. Physikalisches Institut, Georg-August-Universität Göttingen, Göttingen, Germany
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Département de Physique Nucléaire et Corpusculaire, Université de Genève, Genève, Switzerland
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Dipartimento di Fisica, Università di Genova, Genova, Switzerland
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INFN Sezione di Genova, Genoa, Italy
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II. Physikalisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany
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SUPA - School of Physics and Astronomy, University of Glasgow, Glasgow, UK
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LPSC, Université Grenoble Alpes, CNRS/IN2P3, Grenoble INP, Grenoble, France
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Laboratory for Particle Physics and Cosmology, Harvard University, Cambridge, MA, USA
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Department of Modern Physics and State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, USA
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Institute of Frontier and Interdisciplinary Science and Key Laboratory of Particle Physics and Particle Irradiation (MOE), Shandong University, Qingdao, USA
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School of Physics and Astronomy, Shanghai Jiao Tong University, KLPPAC-MoE, SKLPPC, Shanghai, USA
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Tsung-Dao Lee Institute, Shanghai, China
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Kirchhoff-Institut für Physik, Ruprecht-Karls-Universität Heidelberg, Heidelberg, China
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Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
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Faculty of Applied Information Science, Hiroshima Institute of Technology, Hiroshima, Japan
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Department of Physics, Chinese University of Hong Kong, Shatin, N.T., Hong Kong, Japan
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Department of Physics, University of Hong Kong, Hong Kong, Japan
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Department of Physics and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
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Department of Physics, Indiana University, Bloomington, IN, USA
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INFN Gruppo Collegato di Udine, Sezione di Trieste, Udine, USA
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ICTP, Trieste, USA
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Dipartimento Politecnico di Ingegneria e Architettura, Università di Udine, Udine, Italy
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INFN Sezione di Lecce, Zona Monte, Italy
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Dipartimento di Matematica e Fisica, Università del Salento, Lecce, Italy
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INFN Sezione di Milano, Milan, Italy
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Dipartimento di Fisica, Università di Milano, Milano, Italy
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INFN Sezione di Napoli, Naples, Italy
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Dipartimento di Fisica, Università di Napoli, Napoli, Italy
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INFN Sezione di Pavia, Pavia, Italy
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Dipartimento di Fisica, Università di Pavia, Pavia, Italy
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INFN Sezione di Pisa, Pisa, Italy
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Dipartimento di Fisica E. Fermi, Università di Pisa, Pisa, Italy
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INFN Sezione di Roma, Rome, Italy
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Dipartimento di Fisica, Sapienza Università di Roma, Rome, Italy
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INFN Sezione di Roma Tor Vergata, Rome, Italy
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Dipartimento di Fisica, Università di Roma Tor Vergata, Rome, Italy
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INFN Sezione di Roma Tre, Rome, Italy
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Dipartimento di Matematica e Fisica, Università Roma Tre, Rome, Italy
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INFN-TIFPA, Trento, Italy
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Università degli Studi di Trento, Trento, Italy
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Institut für Astro- und Teilchenphysik, Leopold-Franzens-Universität, Innsbruck, Austria
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University of Iowa, Iowa City, IA, USA
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Department of Physics and Astronomy, Iowa State University, Ames, IA, USA
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Joint Institute for Nuclear Research, Dubna, Russia
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Departamento de Engenharia Elétrica, Universidade Federal de Juiz de Fora (UFJF), Juiz de Fora, Russia
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Universidade Federal do Rio De Janeiro COPPE/EE/IF, Rio de Janeiro, Russia
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Universidade Federal de São João del Rei (UFSJ), São João del Rei, Russia
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Instituto de Física, Universidade de São Paulo, São Paulo, Brazil
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KEK, High Energy Accelerator Research Organization, Tsukuba, Japan
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Graduate School of Science, Kobe University, Kobe, Japan
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AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Krakow, Japan
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Marian Smoluchowski Institute of Physics, Jagiellonian University, Krakow, Poland
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Institute of Nuclear Physics Polish Academy of Sciences, Krakow, Poland
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Faculty of Science, Kyoto University, Kyoto, Japan
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Kyoto University of Education, Kyoto, Japan
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Research Center for Advanced Particle Physics and Department of Physics, Kyushu University, Fukuoka, Japan
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Instituto de Física La Plata, Universidad Nacional de La Plata and CONICET, La Plata, Argentina
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Physics Department, Lancaster University, Lancaster, UK
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Oliver Lodge Laboratory, University of Liverpool, Liverpool, UK
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Department of Experimental Particle Physics, Jožef Stefan Institute and Department of Physics, University of Ljubljana, Ljubljana, Slovenia
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School of Physics and Astronomy, Queen Mary University of London, London, UK
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Department of Physics, Royal Holloway University of London, Egham, UK
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Department of Physics and Astronomy, University College London, London, UK
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Louisiana Tech University, Ruston, LA, USA
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Fysiska institutionen, Lunds universitet, Lund, Sweden
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Centre de Calcul de l’Institut National de Physique Nucléaire et de Physique des Particules (IN2P3), Villeurbanne, France
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Departamento de Física Teorica C-15 and CIAFF, Universidad Autónoma de Madrid, Madrid, Spain
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Institut für Physik, Universität Mainz, Mainz, Germany
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School of Physics and Astronomy, University of Manchester, Manchester, UK
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CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille, France
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Department of Physics, University of Massachusetts, Amherst, MA, USA
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Department of Physics, McGill University, Montreal, QC, Canada
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School of Physics, University of Melbourne, Victoria, Australia
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Department of Physics, University of Michigan, Ann Arbor, MI, USA
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Department of Physics and Astronomy, Michigan State University, East Lansing, MI, USA
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B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Minsk, Belarus
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Research Institute for Nuclear Problems of Byelorussian State University, Minsk, Belarus
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Group of Particle Physics, University of Montreal, Montreal, QC, Canada
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P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Moscow, Russia
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Institute for Theoretical and Experimental Physics of the National Research Centre Kurchatov Institute, Moscow, Russia
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National Research Nuclear University MEPhI, Moscow, Russia
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D.V. Skobeltsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Moscow, Russia
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Fakultät für Physik, Ludwig-Maximilians-Universität München, München, Germany
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Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), München, Germany
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Nagasaki Institute of Applied Science, Nagasaki, Japan
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Graduate School of Science and Kobayashi-Maskawa Institute, Nagoya University, Nagoya, Japan
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Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM, USA
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Institute for Mathematics, Astrophysics and Particle Physics, Radboud University Nijmegen/Nikhef, Nijmegen, The Netherlands
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Nikhef National Institute for Subatomic Physics and University of Amsterdam, Amsterdam, The Netherlands
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Department of Physics, Northern Illinois University, DeKalb, IL, USA
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Budker Institute of Nuclear Physics and NSU, SB RAS, Novosibirsk, USA
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Novosibirsk State University Novosibirsk, Novosibirsk, Russia
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Institute for High Energy Physics of the National Research Centre Kurchatov Institute, Protvino, Russia
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Department of Physics, New York University, New York, NY, USA
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Ohio State University, Columbus, OH, USA
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Faculty of Science, Okayama University, Okayama, Japan
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Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK, USA
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Department of Physics, Oklahoma State University, Stillwater, OK, USA
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Palacký University, RCPTM, Joint Laboratory of Optics, Olomouc, Czech Republic
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Center for High Energy Physics, University of Oregon, Eugene, OR, USA
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LAL, Université Paris-Sud, CNRS/IN2P3, Université Paris-Saclay, Orsay, France
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Graduate School of Science, Osaka University, Osaka, Japan
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Department of Physics, University of Oslo, Oslo, Norway
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Department of Physics, Oxford University, Oxford, UK
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LPNHE, Sorbonne Université, Paris Diderot Sorbonne Paris Cité, CNRS/IN2P3, Paris, France
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Department of Physics, University of Pennsylvania, Philadelphia, PA, USA
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Konstantinov Nuclear Physics Institute of National Research Centre “Kurchatov Institute”, PNPI, St. Petersburg, Russia
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Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA, USA
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Laboratório de Instrumentação e Física Experimental de Partículas-LIP, Austin, USA
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Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, Lisboa, USA
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Departamento de Física, Universidade de Coimbra, Coimbra, USA
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Centro de Física Nuclear da Universidade de Lisboa, Lisboa, USA
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Departamento de Física, Universidade do Minho, Braga, USA
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Universidad de Granada, Granada, Spain
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Dep Física and CEFITEC of Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
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Institute of Physics of the Czech Academy of Sciences, Prague, Czech Republic
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Czech Technical University in Prague, Prague, Czech Republic
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Charles University, Faculty of Mathematics and Physics, Prague, Czech Republic
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Particle Physics Department, Rutherford Appleton Laboratory, Didcot, UK
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IRFU, CEA, Université Paris-Saclay, Gif-sur-Yvette, France
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Santa Cruz Institute for Particle Physics, University of California Santa Cruz, Santa Cruz, CA, USA
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Departamento de Física, Pontificia Universidad Católica de Chile, Santiago, USA
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Departamento de Física, Universidad Técnica Federico Santa María, Valparaíso, Chile
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Department of Physics, University of Washington, Seattle, WA, USA
200
Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
201
Department of Physics, Shinshu University, Nagano, Japan
202
Department Physik, Universität Siegen, Siegen, Germany
203
Department of Physics, Simon Fraser University, Burnaby, BC, Canada
204
SLAC National Accelerator Laboratory, Stanford, CA, USA
205
Physics Department, Royal Institute of Technology, Stockholm, Sweden
206
Departments of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
207
Department of Physics and Astronomy, University of Sussex, Brighton, UK
208
School of Physics, University of Sydney, Sydney, Australia
209
Institute of Physics, Academia Sinica, Taipei, Taiwan
210
E. Andronikashvili Institute of Physics, Iv. Javakhishvili Tbilisi State University, Tbilisi, Taiwan
211
High Energy Physics Institute, Tbilisi State University, Tbilisi, Georgia
212
Department of Physics, Technion, Israel Institute of Technology, Haifa, Israel
213
Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel
214
Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, Greece
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International Center for Elementary Particle Physics and Department of Physics, University of Tokyo, Tokyo, Japan
216
Graduate School of Science and Technology, Tokyo Metropolitan University, Tokyo, Japan
217
Department of Physics, Tokyo Institute of Technology, Tokyo, Japan
218
Tomsk State University, Tomsk, Russia
219
Department of Physics, University of Toronto, Toronto, ON, Canada
220
TRIUMF, Vancouver, BC, Canada
221
Department of Physics and Astronomy, York University, Toronto, ON, Canada
222
Division of Physics and Tomonaga Center for the History of the Universe, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Japan
223
Department of Physics and Astronomy, Tufts University, Medford, MA, USA
224
Department of Physics and Astronomy, University of California Irvine, Irvine, CA, USA
225
Department of Physics and Astronomy, University of Uppsala, Uppsala, Sweden
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Department of Physics, University of Illinois, Urbana, IL, USA
227
Instituto de Física Corpuscular (IFIC), Centro Mixto Universidad de Valencia - CSIC, Valencia, Spain
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Department of Physics, University of British Columbia, Vancouver, BC, Canada
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Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada
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Fakultät für Physik und Astronomie, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
231
Department of Physics, University of Warwick, Coventry, UK
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Waseda University, Tokyo, Japan
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Department of Particle Physics, Weizmann Institute of Science, Rehovot, Israel
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Department of Physics, University of Wisconsin, Madison, WI, USA
235
Fakultät für Mathematik und Naturwissenschaften, Fachgruppe Physik, Bergische Universität Wuppertal, Wuppertal, Germany
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Department of Physics, Yale University, New Haven, CT, USA
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Yerevan Physics Institute, Yerevan, Armenia
238
CERN, 1211, Geneva 23, Switzerland
* e-mail: atlas.publications@cern.ch
Received:
11
February
2019
Accepted:
18
May
2019
Published online:
7
June
2019
This paper describes a search for pairs of neutral, long-lived particles decaying in the ATLAS calorimeter. Long-lived particles occur in many extensions to the Standard Model and may elude searches for new promptly decaying particles. The analysis considers neutral, long-lived scalars with masses between 5 and 400 GeV, produced from decays of heavy bosons with masses between 
and 
GeV, where the long-lived scalars decay into Standard Model fermions. The analysis uses either 
or 
of data (depending on the trigger) recorded in 2016 at the LHC with the ATLAS detector in proton–proton collisions at a centre-of-mass energy of 13 TeV. No significant excess is observed, and limits are reported on the production cross section times branching ratio as a function of the proper decay length of the long-lived particles.
© CERN for the benefit of the ATLAS collaboration, 2019
