Observation of a cross-section enhancement near the t t ¯ production threshold in s = 13 TeV pp collisions with the ATLAS detector
Year: 2026
Type: article
Abstract: A measurement of t t ¯ production is presented in the invariant-mass region near the pair production threshold, m t t ¯ ∼ 345 GeV, in final states with two charged leptons and multiple jets. The measurement is based on 140 fb − 1 of proton–proton collision data collected at s = 13 TeV with the ATLAS detector at the Large Hadron Collider. The data are compared to two models of t t ¯ production: a baseline model including only perturbative quantum chromodynamics (pQCD) predictions for the hard process at approximate next-to-next-to leading order accuracy in the strong coupling, and an extended model that, in addition, incorporates non-relativistic QCD simulations that also include the formation of colour-singlet quasi-bound-states near the t t ¯ threshold. The agreement between the data and the models is quantified via a profile-likelihood fit to the reconstructed m t t ¯ distributions, in bins of two angular observables sensitive to spin-correlations in the t t ¯ system. An excess of events is observed over the baseline pQCD prediction, with an observed significance over 8 standard deviations. This excess is consistent with the formation of colour-singlet and spin-singlet S -wave quasi-bound t t ¯ states, as predicted by non-relativistic QCD, and corresponds to an observed cross-section of 9.3 − 1.3 + 1.4 pb.
Source: Reports on Progress in Physics
Author: The ATLAS Collaboration
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,680
Funders: National Science Foundation, U.S. Department of Energy, John Templeton Foundation, Alexander von Humboldt-Stiftung, Canarie, TRIUMF, CERN, UK Research and Innovation, Centres de Recerca de Catalunya, Türkiye Enerji, Nükleer ve Maden Araştırma Kurumu, Leverhulme Trust, Royal Society, European Commission, Deutsche Forschungsgemeinschaft, Agence Nationale de la Recherche, Ministry of Education, Culture, Sports, Science and Technology, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Danmarks Grundforskningsfond, Fundação de Amparo à Pesquisa do Estado de São Paulo, National Natural Science Foundation of China, Ministerstvo Školství, Mládeže a Tělovýchovy, Grantová Agentura České Republiky, Austrian Science Fund, Carl Tryggers Stiftelse för Vetenskaplig Forskning, Generalitat de Catalunya, Ministry of Science and Technology of the People's Republic of China, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Generalitat Valenciana, Bundesministerium für Wissenschaft, Forschung und Wirtschaft, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Knut och Alice Wallenbergs Stiftelse, Max-Planck-Gesellschaft, Vetenskapsrådet, Ministerstwo Edukacji i Nauki, Centre National de la Recherche Scientifique, Ministerio de Ciencia e Innovación, Norges Forskningsråd, Centre National pour la Recherche Scientifique et Technique, Forskningsrådet om Hälsa, Arbetsliv och Välfärd, Narodowa Agencja Wymiany Akademickiej, Agencia Nacional de Investigación y Desarrollo, National Science and Technology Council, Horizon 2020 Framework Programme, Natural Sciences and Engineering Research Council of Canada, Science and Technology Facilities Council, Japan Society for the Promotion of Science, Fundação para a Ciência e a Tecnologia, Agència de Gestió d'Ajuts Universitaris i de Recerca, Agencia Nacional de Promoción Científica y Tecnológica, British Columbia Knowledge Development Fund, European Regional Development Fund, Agencia Estatal de Investigación, Institut National de Physique Nucléaire et de Physique des Particules, European Social Fund, H2020 European Research Council, H2020 Marie Skłodowska-Curie Actions, HORIZON EUROPE Marie Sklodowska-Curie Actions
Awards: G1141912172, G1427383953, Experimental probes of electroweak baryogenesis at LHC, G1561925909, G1728778727, G1775808281, G1823627807, G190755355, THE MEASUREMENT OF THE HIGGS BOSON COUPLINGS AND SEARCH FOR NEW PHYSICS AT THE LHC WITH THE ATLAS DETECTOR, G1958486911, G2070970228, G2156478173, G2165917191, G2217132868, Searching for pairs of scalar particles at the LHC, Probing the ground state of the Universe with Higgs boson pairs, G2371548206, G2380187409, G2406373334, Development of the Energy Frontier and International Human Resources toward Unified Understanding of Interaction, Search for Dark Matter with Long Lived Particles at the LHC, G2614460161, G2656935537, G2677629327, G2678520069, G272265032, SEARCH FOR MULTIQUARK STATES IN NUCLEAR COLLISIONS AND IMPROVING MUON DETECTION WITH THE NEW SMALL WHEELS DETECTORS OF ATLAS, G2748086542, G291036901, G295657101, G3216801164, G3492800960, Advanced TRacking Algorithms for Particle Physics, G3572990523, G3586395236, Turning noise into data: a discovery strategy for new weakly-interacting physics, Journey to the Dark Side: Exploring Dark Meson Decays in Unconventional Signatures at Colliders with Machine Learning, G370133677, G3735356012, G3783317134, G3810236772, オーキシンとくにインドール酢酸の生物界における分布と細胞分裂に及ぼす影響, G3869848141, G3900039137, G4085707338, G4104407935, G4138653504, Discovering new phenomena with pairs of top quarks, G4264918310, G4272034983, Turning noise into data: a discovery strategy for new weakly-interacting physics, G4396925471, G4413722245, G4473368111, G4478232191, G4508289328, G4586921159, EXPLORING THE STANDARD MODEL THROUGH LEPTON INTERACTIONS WITH THE ATLAS AND FUTURE DETECTORS., G4654690619, Time4Discovery: Searching for long-lived particles with novel use of timing information in Run 3 of the LHC, G4697343757, G4711507462, G4775162344, G4797188016, G480074419, LONG-LIVED PARTICLES AS MEANS OF NEW PHYSICS IN PARTICLE COLLIDERS, G491635419, G4947326599, G5101457884, Quantum measurement, locality, and reality in high energy experiments, G5200785586, G5279931776, G5280381206, G5302535838, In-medium radiation of quarks and gluons with the ATLAS detector at the LHC, G5438923238, G545007060, G5547464225, Ethical deliberation. The contribution of dialogism and erotetic logic., G5570207115, Advancing the Higgs Frontier, G5629441754, G5765983289, G5815377982, REAL-time discovery strategies for DARK matter and dark sector signals at the ATLAS detector with Run-3 LHC data, G5905307082, G5983053213, G626454535, G6351313000, G6362110921, G6438247056, Searches for Higgs boson pairs in the ATLAS experiment at the LHC to probe physics in and beyond the Standard Model, G6809819652, G6813029366, G6823224962, G6914281650, G698819318, G7286431674, G7303439971, G7367692441, G7448368246, STUDY OF HEAVY-FLAVOR ENERGY LOSS IN QUARK-GLUON-PLASMA, Geometric deep learning for high-energy particle tracking, G7766498731, G7787206679, G7795150481, G7920589926, Machine learning for Sciences and Humanities, G7938408761, Challenging AI with Challenges from Physics: How to solve fundamental problems in Physics by AI and vice versa, G8140083606, G8147196582, Präzisionstests des Standardmodells unter der Verwendung von geboosteten W/ZBosonen am Large Hadron Collider, G8347645112, G8601313065, Exploration of the new physics beyond the Standard Model with rare processes of the Higgs boson, G8726098666, G8798160806, G884207649, DiHiggs In VBF Events : Exploring the Higgs boson properties through vector boson fusion HH production, G8920660035, G8945569637, G8956900062, タウ粒子識別技術の先鋭化による暗黒物質研究の開拓, G948983577, G969889393
OpenAlex ID: W7154609393