Eur. Phys. J. C (2026) 86: 247
https://doi.org/10.1140/epjc/s10052-025-15218-2

Regular Article - Experimental Physics

Search for Beyond the Standard Model physics with anomaly detection in multilepton final states in pp collisions at $\sqrt{s}=13\text{TeV}$ with the ATLAS detector

¹ Department of Physics, University of Adelaide, Adelaide, Australia
² Department of Physics, University of Alberta, Edmonton, AB, Canada
³ Department of Physics, Ankara University, Ankara, Turkey
⁴ Division of Physics, TOBB University of Economics and Technology, Ankara, Turkey
⁵ LAPP, Université Savoie Mont Blanc, CNRS/IN2P3, Annecy, France
⁶ APC, Université Paris Cité, CNRS/IN2P3, Paris, France
⁷ High Energy Physics Division, Argonne National Laboratory, Argonne, IL, USA
⁸ Department of Physics, University of Arizona, Tucson, AZ, USA
⁹ Department of Physics, University of Texas at Arlington, Arlington, TX, USA
¹⁰ Physics Department, National and Kapodistrian University of Athens, Athens, Greece
¹¹ Physics Department, National Technical University of Athens, Zografou, Greece
¹² Department of Physics, University of Texas at Austin, Austin, TX, USA
¹³ Institute of Physics, Azerbaijan Academy of Sciences, Baku, Azerbaijan
¹⁴ Institut de Física d’Altes Energies (IFAE), Barcelona Institute of Science and Technology, Barcelona, Spain
¹⁵ Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China
¹⁶ Physics Department, Tsinghua University, Beijing, China
¹⁷ Institute of Physics, University of Belgrade, Belgrade, Serbia
¹⁸ Department for Physics and Technology, University of Bergen, Bergen, Norway
¹⁹ Physics Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
²⁰ University of California, Berkeley, CA, USA
²¹ Institut für Physik, Humboldt Universität zu Berlin, Berlin, Germany
²² Albert Einstein Center for Fundamental Physics and Laboratory for High Energy Physics, University of Bern, Bern, Switzerland
²³ School of Physics and Astronomy, University of Birmingham, Birmingham, UK
²⁴ Department of Physics, Bogazici University, Istanbul, Turkey
²⁵ Department of Physics Engineering, Gaziantep University, Gaziantep, Turkey
²⁶ Department of Physics, Istanbul University, Istanbul, Turkey
²⁷ Facultad de Ciencias y Centro de Investigaciónes, Universidad Antonio Nariño, Bogotá, Colombia
²⁸ Departamento de Física, Universidad Nacional de Colombia, Bogotá, Colombia
²⁹ Dipartimento di Fisica e Astronomia A. Righi, Università di Bologna, Bologna, Italy
³⁰ INFN Sezione di Bologna, Bologna, Italy
³¹ Physikalisches Institut, Universität Bonn, Bonn, Germany
³² Department of Physics, Boston University, Boston, MA, USA
³³ Department of Physics, Brandeis University, Waltham, MA, USA
³⁴ Transilvania University of Brasov, Brasov, Romania
³⁵ Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest, Romania
³⁶ Department of Physics, Alexandru Ioan Cuza University of Iasi, Iasi, Romania
³⁷ Physics Department, National Institute for Research and Development of Isotopic and Molecular Technologies, Cluj-Napoca, Romania
³⁸ National University of Science and Technology Politechnica, Bucharest, Romania
³⁹ West University in Timisoara, Timisoara, Romania
⁴⁰ Faculty of Physics, University of Bucharest, Bucharest, Romania
⁴¹ Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovak Republic
⁴² Department of Subnuclear Physics, Institute of Experimental Physics of the Slovak Academy of Sciences, Kosice, Slovak Republic
⁴³ Physics Department, Brookhaven National Laboratory, Upton, NY, USA
⁴⁴ Departamento de Física, y CONICET, Facultad de Ciencias Exactas y Naturales, Instituto de Física de Buenos Aires (IFIBA), Universidad de Buenos Aires, Buenos Aires, Argentina
⁴⁵ California State University, Long Beach, CA, USA
⁴⁶ Cavendish Laboratory, University of Cambridge, Cambridge, UK
⁴⁷ Department of Physics, University of Cape Town, Cape Town, South Africa
⁴⁸ iThemba Labs, Western Cape, South Africa
⁴⁹ Department of Mechanical Engineering Science, University of Johannesburg, Johannesburg, South Africa
⁵⁰ National Institute of Physics, University of the Philippines Diliman (Philippines), Quezon City, Philippines
⁵¹ Department of Physics, Stellenbosch University, Matieland, Stellenbosch, South Africa
⁵² School of Agriculture and Science, Mathematics, University of KwaZulu-Natal, Westville, South Africa
⁵³ Department of Physics, University of South Africa, Pretoria, South Africa
⁵⁴ Department of Mechanical and Aeronautical Engineering, University of Pretoria, Pretoria, South Africa
⁵⁵ University of Zululand, KwaDlangezwa, Empangeni, South Africa
⁵⁶ School of Physics, University of the Witwatersrand, Johannesburg, South Africa
⁵⁷ Department of Physics, Carleton University, Ottawa, ON, Canada
⁵⁸ Faculté des Sciences Ain Chock, Université Hassan II de Casablanca, Casablanca, Morocco
⁵⁹ Faculté des Sciences, Université Ibn-Tofail, Kenitra, Morocco
⁶⁰ Faculté des Sciences Semlalia, Université Cadi Ayyad, LPHEA-Marrakech, Marrakech, Morocco
⁶¹ LPMR, Faculté des Sciences, Université Mohamed Premier, Oujda, Morocco
⁶² Faculté des sciences, Université Mohammed V, Rabat, Morocco
⁶³ Institute of Applied Physics, Mohammed VI Polytechnic University, Ben Guerir, Morocco
⁶⁴ CERN, Geneva, Switzerland
⁶⁵ Affiliated with an Institute Formerly Covered by a Cooperation Agreement with CERN, Geneva, Switzerland
⁶⁶ Affiliated with an International Laboratory Covered by a Cooperation agreement with CERN, Geneva, Switzerland
⁶⁷ Enrico Fermi Institute, University of Chicago, Chicago, IL, USA
⁶⁸ LPC, Université Clermont Auvergne, CNRS/IN2P3, Clermont-Ferrand, France
⁶⁹ Nevis Laboratory, Columbia University, Irvington, NY, USA
⁷⁰ Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
⁷¹ Dipartimento di Fisica, Università della Calabria, Rende, Italy
⁷² INFN Gruppo Collegato di Cosenza, Laboratori Nazionali di Frascati, Frascati, Italy
⁷³ Physics Department, Southern Methodist University, Dallas, TX, USA
⁷⁴ National Centre for Scientific Research “Demokritos”, Agia Paraskevi, Greece
⁷⁵ Department of Physics, Stockholm University, Stockholm, Sweden
⁷⁶ Oskar Klein Centre, Stockholm, Sweden
⁷⁷ Deutsches Elektronen-Synchrotron DESY, Hamburg and Zeuthen, Germany
⁷⁸ Fakultät Physik, Technische Universität Dortmund, Dortmund, Germany
⁷⁹ Institut für Kern-und Teilchenphysik, Technische Universität Dresden, Dresden, Germany
⁸⁰ Department of Physics, Duke University, Durham, NC, USA
⁸¹ SUPA-School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
⁸² INFN e Laboratori Nazionali di Frascati, Frascati, Italy
⁸³ Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
⁸⁴ II. Physikalisches Institut, Georg-August-Universität Göttingen, Göttingen, Germany
⁸⁵ Département de Physique Nucléaire et Corpusculaire, Université de Genève, Geneva, Switzerland
⁸⁶ Dipartimento di Fisica, Università di Genova, Genoa, Italy
⁸⁷ INFN Sezione di Genova, Genoa, Italy
⁸⁸ II. Physikalisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany
⁸⁹ SUPA-School of Physics and Astronomy, University of Glasgow, Glasgow, UK
⁹⁰ LPSC, Université Grenoble Alpes, CNRS/IN2P3, Grenoble INP, Grenoble, France
⁹¹ Laboratory for Particle Physics and Cosmology, Harvard University, Cambridge, MA, USA
⁹² Department of Modern Physics and State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, China
⁹³ Kirchhoff-Institut für Physik, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
⁹⁴ Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
⁹⁵ Department of Physics, Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China
⁹⁶ Department of Physics, University of Hong Kong, Hong Kong, China
⁹⁷ Department of Physics and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
⁹⁸ Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
⁹⁹ IJCLab, Université Paris-Saclay, CNRS/IN2P3, 91405, Orsay, France
¹⁰⁰ Centro Nacional de Microelectrónica (IMB-CNM-CSIC), Barcelona, Spain
¹⁰¹ Department of Physics, Indiana University, Bloomington, IN, USA
¹⁰² INFN Gruppo Collegato di Udine, Sezione di Trieste, Udine, Italy
¹⁰³ ICTP, Trieste, Italy
¹⁰⁴ Dipartimento Politecnico di Ingegneria e Architettura, Università di Udine, Udine, Italy
¹⁰⁵ INFN Sezione di Lecce, Lecce, Italy
¹⁰⁶ Dipartimento di Matematica e Fisica, Università del Salento, Lecce, Italy
¹⁰⁷ INFN Sezione di Milano, Milan, Italy
¹⁰⁸ Dipartimento di Fisica, Università di Milano, Milan, Italy
¹⁰⁹ INFN Sezione di Napoli, Naples, Italy
¹¹⁰ Dipartimento di Fisica, Università di Napoli, Naples, Italy
¹¹¹ INFN Sezione di Pavia, Pavia, Italy
¹¹² Dipartimento di Fisica, Università di Pavia, Pavia, Italy
¹¹³ INFN Sezione di Pisa, Pisa, Italy
¹¹⁴ Dipartimento di Fisica E. Fermi, Università di Pisa, Pisa, Italy
¹¹⁵ INFN Sezione di Roma, Rome, Italy
¹¹⁶ Dipartimento di Fisica, Sapienza Università di Roma, Rome, Italy
¹¹⁷ INFN Sezione di Roma Tor Vergata, Rome, Italy
¹¹⁸ Dipartimento di Fisica, Università di Roma Tor Vergata, Rome, Italy
¹¹⁹ INFN Sezione di Roma Tre, Rome, Italy
¹²⁰ Dipartimento di Matematica e Fisica, Università Roma Tre, Rome, Italy
¹²¹ INFN-TIFPA, Trento, Italy
¹²² Università degli Studi di Trento, Trento, Italy
¹²³ Department of Astro and Particle Physics, Universität Innsbruck, Innsbruck, Austria
¹²⁴ University of Iowa, Iowa City, IA, USA
¹²⁵ Department of Physics and Astronomy, Iowa State University, Ames, IA, USA
¹²⁶ Istinye University, Sariyer, Istanbul, Turkey
¹²⁷ Departamento de Engenharia Elétrica, Universidade Federal de Juiz de Fora (UFJF), Juiz de Fora, Brazil
¹²⁸ Universidade Federal do Rio De Janeiro COPPE/EE/IF, Rio de Janeiro, Brazil
¹²⁹ Instituto de Física, Universidade de São Paulo, São Paulo, Brazil
¹³⁰ Rio de Janeiro State University, Rio de Janeiro, Brazil
¹³¹ Federal University of Bahia, Bahia, Brazil
¹³² KEK, High Energy Accelerator Research Organization, Tsukuba, Japan
¹³³ Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
¹³⁴ University of Sharjah, Sharjah, United Arab Emirates
¹³⁵ Graduate School of Science, Kobe University, Kobe, Japan
¹³⁶ Faculty of Physics and Applied Computer Science, AGH University of Krakow, Kraków, Poland
¹³⁷ Marian Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland
¹³⁸ Institute of Nuclear Physics Polish Academy of Sciences, Kraków, Poland
¹³⁹ Faculty of Science, Kyoto University, Kyoto, Japan
¹⁴⁰ Research Center for Advanced Particle Physics and Department of Physics, Kyushu University, Fukuoka, Japan
¹⁴¹ L2IT, Université de Toulouse, CNRS/IN2P3, UPS, Toulouse, France
¹⁴² Instituto de Física La Plata, Universidad Nacional de La Plata and CONICET, La Plata, Argentina
¹⁴³ Physics Department, Lancaster University, Lancaster, UK
¹⁴⁴ Oliver Lodge Laboratory, University of Liverpool, Liverpool, UK
¹⁴⁵ Department of Experimental Particle Physics, Jožef Stefan Institute and Department of Physics, University of Ljubljana, Ljubljana, Slovenia
¹⁴⁶ Department of Physics and Astronomy, Queen Mary University of London, London, UK
¹⁴⁷ Department of Physics, Royal Holloway University of London, Egham, UK
¹⁴⁸ Department of Physics and Astronomy, University College London, London, UK
¹⁴⁹ Louisiana Tech University, Ruston, LA, USA
¹⁵⁰ Fysiska institutionen, Lunds universitet, Lund, Sweden
¹⁵¹ Departamento de Física Teorica C-15 and CIAFF, Universidad Autónoma de Madrid, Madrid, Spain
¹⁵² Institut für Physik, Universität Mainz, Mainz, Germany
¹⁵³ School of Physics and Astronomy, University of Manchester, Manchester, UK
¹⁵⁴ CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille, France
¹⁵⁵ Department of Physics, University of Massachusetts, Amherst, MA, USA
¹⁵⁶ Department of Physics, McGill University, Montreal, QC, Canada
¹⁵⁷ School of Physics, University of Melbourne, Victoria, Australia
¹⁵⁸ Department of Physics, University of Michigan, Ann Arbor, MI, USA
¹⁵⁹ Department of Physics and Astronomy, Michigan State University, East Lansing, MI, USA
¹⁶⁰ Group of Particle Physics, University of Montreal, Montreal, QC, Canada
¹⁶¹ Fakultät für Physik, Ludwig-Maximilians-Universität München, Munich, Germany
¹⁶² Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Munich, Germany
¹⁶³ Graduate School of Science and Kobayashi-Maskawa Institute, Nagoya University, Nagoya, Japan
¹⁶⁴ Department of Physics, Nanjing University, Nanjing, China
¹⁶⁵ School of Science, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
¹⁶⁶ University of Chinese Academy of Science (UCAS), Beijing, China
¹⁶⁷ Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM, USA
¹⁶⁸ Institute for Mathematics, Astrophysics and Particle Physics, Radboud University/Nikhef, Nijmegen, The Netherlands
¹⁶⁹ Nikhef National Institute for Subatomic Physics and University of Amsterdam, Amsterdam, The Netherlands
¹⁷⁰ Department of Physics, Northern Illinois University, DeKalb, IL, USA
¹⁷¹ New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
¹⁷² United Arab Emirates University, Al Ain, United Arab Emirates
¹⁷³ Department of Physics, New York University, New York, NY, USA
¹⁷⁴ Ochanomizu University, Otsuka, Bunkyo-ku, Tokyo, Japan
¹⁷⁵ Ohio State University, Columbus, OH, USA
¹⁷⁶ Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK, USA
¹⁷⁷ Department of Physics, Oklahoma State University, Stillwater, OK, USA
¹⁷⁸ Joint Laboratory of Optics, Palacký University, Olomouc, Czech Republic
¹⁷⁹ Institute for Fundamental Science, University of Oregon, Eugene, OR, USA
¹⁸⁰ Graduate School of Science, University of Osaka, Osaka, Japan
¹⁸¹ Department of Physics, University of Oslo, Oslo, Norway
¹⁸² Department of Physics, Oxford University, Oxford, UK
¹⁸³ LPNHE, Sorbonne Université, Université Paris Cité, CNRS/IN2P3, Paris, France
¹⁸⁴ Department of Physics, University of Pennsylvania, Philadelphia, PA, USA
¹⁸⁵ Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA, USA
¹⁸⁶ Laboratório de Instrumentação e Física Experimental de Partículas-LIP, Lisbon, Portugal
¹⁸⁷ Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
¹⁸⁸ Departamento de Física, Universidade de Coimbra, Coimbra, Portugal
¹⁸⁹ Centro de Física Nuclear da Universidade de Lisboa, Lisbon, Portugal
¹⁹⁰ Departamento de Física, Escola de Ciências, Universidade do Minho, Braga, Portugal
¹⁹¹ Departamento de Física Teórica y del Cosmos, Universidad de Granada, Granada, Spain
¹⁹² Departamento de Física, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
¹⁹³ Institute of Physics of the Czech Academy of Sciences, Prague, Czech Republic
¹⁹⁴ Czech Technical University in Prague, Prague, Czech Republic
¹⁹⁵ Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
¹⁹⁶ Particle Physics Department, Rutherford Appleton Laboratory, Didcot, UK
¹⁹⁷ IRFU, CEA, Université Paris-Saclay, Gif-sur-Yvette, France
¹⁹⁸ Santa Cruz Institute for Particle Physics, University of California Santa Cruz, Santa Cruz, CA, USA
¹⁹⁹ Departamento de Física, Pontificia Universidad Católica de Chile, Santiago, Chile
²⁰⁰ Millennium Institute for Subatomic Physics at High Energy Frontier (SAPHIR), Santiago, Chile
²⁰¹ Instituto de Investigación Multidisciplinario en Ciencia y Tecnología, y Departamento de Física, Universidad de La Serena, La Serena, Chile
²⁰² Department of Physics, Universidad Andres Bello, Santiago, Chile
²⁰³ Universidad San Sebastian, Recoleta, Chile
²⁰⁴ Instituto de Alta Investigación, Universidad de Tarapacá, Arica, Chile
²⁰⁵ Departamento de Física, Universidad Técnica Federico Santa María, Valparaiso, Chile
²⁰⁶ Department of Physics, Institute of Science, Tokyo, Japan
²⁰⁷ Department of Physics, University of Washington, Seattle, WA, USA
²⁰⁸ Institute of Frontier and Interdisciplinary Science and Key Laboratory of Particle Physics and Particle Irradiation (MOE), Shandong University, Qingdao, China
²⁰⁹ School of Physics, Zhengzhou University, Zhengzhou, China
²¹⁰ State Key Laboratory of Dark Matter Physics, School of Physics and Astronomy, Key Laboratory for Particle Astrophysics and Cosmology (MOE), SKLPPC, Shanghai Jiao Tong University, Shanghai, China
²¹¹ State Key Laboratory of Dark Matter Physics, Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, China
²¹² Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
²¹³ Department of Physics, Shinshu University, Nagano, Japan
²¹⁴ Department Physik, Universität Siegen, Siegen, Germany
²¹⁵ Department of Physics, Simon Fraser University, Burnaby, BC, Canada
²¹⁶ SLAC National Accelerator Laboratory, Stanford, CA, USA
²¹⁷ Department of Physics, Royal Institute of Technology, Stockholm, Sweden
²¹⁸ Departments of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA
²¹⁹ Department of Physics and Astronomy, University of Sussex, Brighton, UK
²²⁰ School of Physics, University of Sydney, Sydney, Australia
²²¹ Institute of Physics, Academia Sinica, Taipei, Taiwan
²²² E. Andronikashvili Institute of Physics, Iv. Javakhishvili Tbilisi State University, Tbilisi, Georgia
²²³ High Energy Physics Institute, Tbilisi State University, Tbilisi, Georgia
²²⁴ University of Georgia, Tbilisi, Georgia
²²⁵ Department of Physics, Technion, Israel Institute of Technology, Haifa, Israel
²²⁶ Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv, Israel
²²⁷ Department of Physics, Aristotle University of Thessaloniki, Thessaloníki, Greece
²²⁸ International Center for Elementary Particle Physics and Department of Physics, University of Tokyo, Tokyo, Japan
²²⁹ Graduate School of Science and Technology, Tokyo Metropolitan University, Tokyo, Japan
²³⁰ Department of Physics, University of Toronto, Toronto, ON, Canada
²³¹ TRIUMF, Vancouver, BC, Canada
²³² Department of Physics and Astronomy, York University, Toronto, ON, Canada
²³³ Division of Physics and Tomonaga Center for the History of the Universe, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Japan
²³⁴ Department of Physics and Astronomy, Tufts University, Medford, MA, USA
²³⁵ Department of Physics and Astronomy, University of California Irvine, Irvine, CA, USA
²³⁶ University of West Attica, Athens, Greece
²³⁷ Department of Physics and Astronomy, University of Uppsala, Uppsala, Sweden
²³⁸ Department of Physics, University of Illinois, Urbana, IL, USA
²³⁹ Instituto de Física Corpuscular (IFIC), Centro Mixto Universidad de Valencia-CSIC, Valencia, Spain
²⁴⁰ Department of Physics, University of British Columbia, Vancouver, BC, Canada
²⁴¹ Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada
²⁴² Fakultät für Physik und Astronomie, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
²⁴³ Department of Physics, University of Warwick, Coventry, UK
²⁴⁴ Waseda University, Tokyo, Japan
²⁴⁵ Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot, Israel
²⁴⁶ Department of Physics, University of Wisconsin, Madison, WI, USA
²⁴⁷ Fakultät für Mathematik und Naturwissenschaften, Fachgruppe Physik, Bergische Universität Wuppertal, Wuppertal, Germany
²⁴⁸ Department of Physics, Yale University, New Haven, CT, USA
²⁴⁹ Yerevan Physics Institute, Yerevan, Armenia
²⁵⁰ Affiliated with an Institute Formerly Covered by a Cooperation Agreement with CERN, Geneva, Switzerland
²⁵¹ An-Najah National University, Nablus, Palestine
²⁵² Borough of Manhattan Community College, City University of New York, New York, NY, USA
²⁵³ Center for Interdisciplinary Research and Innovation (CIRI-AUTH), Thessaloníki, Greece
²⁵⁴ Centre of Physics of the Universities of Minho and Porto (CF-UM-UP), Braga, Portugal
²⁵⁵ CERN, Geneva, Switzerland
²⁵⁶ Département de Physique Nucléaire et Corpusculaire, Université de Genève, Geneva, Switzerland
²⁵⁷ Departament de Fisica de la Universitat Autonoma de Barcelona, Barcelona, Spain
²⁵⁸ Department of Financial and Management Engineering, University of the Aegean, Chios, Greece
²⁵⁹ Department of Mathematical Sciences, University of South Africa, Johannesburg, South Africa
²⁶⁰ Department of Modern Physics and State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, China
²⁶¹ Department of Physics, Bolu Abant Izzet Baysal University, Bolu, Turkey
²⁶² Department of Physics, King’s College London, London, UK
²⁶³ Department of Physics, Stanford University, Stanford, CA, USA
²⁶⁴ Department of Physics, Stellenbosch University, Stellenbosch, South Africa
²⁶⁵ Department of Physics, University of Fribourg, Fribourg, Switzerland
²⁶⁶ Department of Physics, University of Thessaly, Vólos, Greece
²⁶⁷ Department of Physics, Westmont College, Santa Barbara, USA
²⁶⁸ Faculty of Physics, Sofia University, ‘St. Kliment Ohridski’, Sofia, Bulgaria
²⁶⁹ Faculty of Physics, University of Bucharest, Bucharest, Romania
²⁷⁰ Hellenic Open University, Patras, Greece
²⁷¹ Henan University, Kaifeng, China
²⁷² Imam Mohammad Ibn Saud Islamic University, Riyadh, Saudi Arabia
²⁷³ Institucio Catalana de Recerca i Estudis Avancats, ICREA, Barcelona, Spain
²⁷⁴ Institut für Experimentalphysik, Universität Hamburg, Hamburg, Germany
²⁷⁵ Institute for Nuclear Research and Nuclear Energy (INRNE) of the Bulgarian Academy of Sciences, Sofia, Bulgaria
²⁷⁶ Institute of Applied Physics, Mohammed VI Polytechnic University, Ben Guerir, Morocco
²⁷⁷ Institute of Particle Physics (IPP), Victoria, Canada
²⁷⁸ Institute of Physics and Technology, Mongolian Academy of Sciences, Ulaanbaatar, Mongolia
²⁷⁹ Institute of Physics, Azerbaijan Academy of Sciences, Baku, Azerbaijan
²⁸⁰ Institute of Theoretical Physics, Ilia State University, Tbilisi, Georgia
²⁸¹ Millennium Institute for Subatomic Physics at High Energy Frontier (SAPHIR), Santiago, Chile
²⁸² National Institute of Physics, University of the Philippines Diliman (Philippines), Quezon City, Philippines
²⁸³ The Collaborative Innovation Center of Quantum Matter (CICQM), Beijing, China
²⁸⁴ TRIUMF, Vancouver, BC, Canada
²⁸⁵ Università di Napoli Parthenope, Naples, Italy
²⁸⁶ University of Chinese Academy of Sciences (UCAS), Beijing, China
²⁸⁷ Department of Physics, University of Colorado Boulder, Colorado, USA
²⁸⁸ University of Sienna, Sienna, Italy
²⁸⁹ Washington College, Chestertown, MD, USA
²⁹⁰ Physics Department, Yeditepe University, Istanbul, Turkey
²⁹¹ CERN, 1211, Geneva 23, Switzerland

^a This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 28 August 2025
Accepted: 17 December 2025
Published online: 11 March 2026

Abstract

A model-agnostic search for Beyond the Standard Model physics is presented, targeting final states with at least four light leptons (electrons or muons). The search regions are separated by event topology and unsupervised machine learning is used to identify anomalous events in the full 140 fb$_{}^{-1}$ of proton–proton collision data collected with the ATLAS detector during Run 2. No significant excess above the Standard Model background expectation is observed. Model-agnostic limits are presented in each topology, along with limits on several benchmark models including vector-like leptons, wino-like charginos and neutralinos, or smuons. Limits are set on the flavourful vector-like lepton model for the first time.