Observation of Production in Pb+Pb Collisions at with the ATLAS Detector
Top-quark pair production is observed in lead–lead ( ) collisions at at the Large Hadron Collider with the ATLAS detector. The data sample was recorded in 2015 and 2018, amounting to an integrated luminosity of . Events with exactly one electron and one muon and at least two jets are selected. Top-quark pair production is measured with an observed (expected) significance of 5.0 (4.1) standard deviations. The measured top-quark pair production cross section is , with a total relative uncertainty of 31%, and is consistent with theoretical predictions using a range of different nuclear parton distribution functions. The observation of this process consolidates the evidence of the existence of all quark flavors in the preequilibrium stage of the quark-gluon plasma at very high energy densities, similar to the conditions present in the early Universe.
© 2025 CERN, for the ATLAS Collaboration 2025 CERN- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
- Sponsoring Organization:
- ’la Caixa’ Foundation; Agència de Gestió d’Ajuts Universitaris i de Recerca; Agence Nationale de la Recherche; Agencia Nacional de Investigación y Desarrollo; Agencia Nacional de Investigación y Desarrollo; Agencia Nacional de Promoción Científica y Tecnológica; Agencia Nacional de Promoción Científica y Tecnológica; Agència de Gestió d’Ajuts Universitaris i de Recerca; Arizona-Nevada Academy of Science; Australian Research Council; Austrian Science Fund; AvH Foundation; Baden-Württemberg Stiftung; Baden-Württemberg Stiftung; Big Data and Quantum Computing; British Columbia Knowledge Development Fund; Brookhaven National Laboratory; Bundesministerium für Bildung und Forschung; Bundesministerium für Wissenschaft, Forschung und Wirtschaft; Bundesministerium für Bildung und Forschung; Bundesministerium für Wissenschaft, Forschung und Wirtschaft; CERN; CRC; Canada Foundation for Innovation; Canarie; Cantons of Bern and Geneva; Carl Tryggers Stiftelse för Vetenskaplig Forskning; Carl Tryggers Stiftelse för Vetenskaplig Forskning; Centre National de la Recherche Scientifique; Centre National pour la Recherche Scientifique et Technique; Centres de Recerca de Catalunya; Chinese Academy of Sciences; Commissariat à l’Énergie Atomique et aux Énergies Alternatives; Commissariat à l’Énergie Atomique et aux Énergies Alternatives; Conselho Nacional de Desenvolvimento Científico e Tecnológico; Conselho Nacional de Desenvolvimento Científico e Tecnológico; DNSRC; DRAC; Danmarks Grundforskningsfond; Deutsche Forschungsgemeinschaft; European Commission; European Regional Development Fund; European Social Fund; Federación Española de Enfermedades Raras; Federación Española de Enfermedades Raras; Fondo Nacional de Desarrollo Científico y Tecnológico; Fondo Nacional de Desarrollo Científico y Tecnológico; Food and Health Bureau; Fundação de Amparo à Pesquisa do Estado de São Paulo; Fundação para a Ciência e a Tecnologia; Fundação de Amparo à Pesquisa do Estado de São Paulo; Fundação para a Ciência e a Tecnologia; Göran Gustafssons Stiftelser; GSRI; Generalitat Valenciana; Generalitat de Catalunya; Grantová Agentura České Republiky; Grantová Agentura České Republiky; Göran Gustafssons Stiftelser; H2020 European Research Council; H2020 Marie Skłodowska-Curie Actions; Helmholtz-Gemeinschaft; Horizon 2020 Framework Programme; ICHEP; ICSC; ICSC-NextGenerationEU; Institut National de Physique Nucléaire et de Physique des Particules; Institut National de Physique Nucléaire et de Physique des Particules; Instituto Nazionale di Fisica Nucleare; Institutul de Fizică Atomică; Investissements d’ Avenir Labex; Investissements d’ Avenir Labex; Israel Academy of Sciences and Humanities; Israel Science Foundation; Italian Center for High Performance Computing; Japan Society for the Promotion of Science; Javna Agencija za Raziskovalno Dejavnost RS; Karlsruhe Institute of Technology; Knut och Alice Wallenbergs Stiftelse; Leverhulme Trust; MINERVA; MNiSW; MOST; MSSR; MSTDI; MVZI; Max-Planck-Gesellschaft; Minciencias; Ministerio de Ciencia e Innovación; Ministerio de Ciencia e Innovación; Ministero dell’Istruzione, dell’Università e della Ricerca; Ministero dell’Istruzione, dell’Università e della Ricerca; Ministerstvo Školství, Mládeže a Tělovýchovy; Ministerstvo Školství, Mládeže a Tělovýchovy; Ministerstwo Edukacji i Nauki; Ministry of Education, Culture, Sports, Science and Technology; Ministry of Science and Technology of the People’s Republic of China; Ministry of Science and Technology of the People’s Republic of China; NDGF; NL-T1; NSRF; Narodowa Agencja Wymiany Akademickiej; Narodowe Centrum Nauki; National Natural Science Foundation of China; National Research Council Canada; National Research Foundation; National Science Foundation; Natural Sciences and Engineering Research Council of Canada; Nederlandse Organisatie voor Wetenschappelijk Onderzoek; Neubauer Family Foundation; Norges Forskningsråd; Norges Forskningsråd; PIC; PRIMUS Research Programme; RAL; RCN; RGC; Royal Society; SERI; SRNSFG; Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung; Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung; Science and Technology Facilities Council; Türkiye Enerji, Nükleer ve Maden Araştırma Kurumu; TRIUMF; Türkiye Enerji, Nükleer ve Maden Araştırma Kurumu; U.S. Department of Energy; US Department of Energy; USDOE; USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25); United States-Israel Binational Science Foundation; Vetenskapsrådet; Vetenskapsrådet; YerPhI; ’la Caixa’ Foundation
- Grant/Contract Number:
- AC02-05CH11231; AC02-76SF00515
- OSTI ID:
- 2549438
- Alternate ID(s):
- OSTI ID: 2588168
OSTI ID: 2588052
OSTI ID: 2587901
- Journal Information:
- Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 14 Vol. 134; ISSN 0031-9007; ISSN PRLTAO
- Publisher:
- American Physical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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