@misc{10481/85677,
year = {2023},
month = {6},
url = {https://hdl.handle.net/10481/85677},
abstract = {This paper presents the observation of four-topquark
(t ¯tt ¯t) production in proton-proton collisions at the
LHC. The analysis is performed using an integrated luminosity
of 140 fb−1 at a centre-of-mass energy of 13 TeVcollected
using the ATLAS detector. Events containing two leptons
with the same electric charge or at least three leptons (electrons
or muons) are selected. Event kinematics are used to
separate signal from background through a multivariate discriminant,
and dedicated control regions are used to constrain
the dominant backgrounds. The observed (expected) significance
of themeasured t ¯tt ¯t signal with respect to the standard
model (SM) background-only hypothesis is 6.1 (4.3) standard
deviations. The t ¯tt ¯t production cross section is measured
to be 22.5+6.6
−5.5 fb, consistent with the SMprediction of
12.0 ± 2.4 fb within 1.8 standard deviations. Data are also
used to set limits on the three-top-quark production cross
section, being an irreducible background not measured previously,
and to constrain the top-Higgs Yukawa coupling and
effective field theory operator coefficients that affect t ¯t t ¯t production.},
organization = {ANPCyT},
organization = {YerPhI, Armenia},
organization = {Australian Research Council},
organization = {BMWFW, Austria},
organization = {Austrian Science Fund (FWF)},
organization = {Azerbaijan National Academy of Sciences (ANAS)},
organization = {Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ)},
organization = {Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)},
organization = {Natural Sciences and Engineering Research Council of Canada (NSERC)},
organization = {Canada Foundation for Innovation},
organization = {National Natural Science Foundation of China (NSFC)},
organization = {MEYS CR, Czech Republic},
organization = {National Research Foundation of Korea},
organization = {Danish Natural Science Research Council},
organization = {Centre National de la Recherche Scientifique (CNRS)},
organization = {CEA-DRF/IRFU, France},
organization = {Federal Ministry of Education & Research (BMBF)},
organization = {Max Planck Society},
organization = {Hong Kong SAR, China},
organization = {Israel Science Foundation},
organization = {Istituto Nazionale di Fisica Nucleare (INFN)},
organization = {Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT)},
organization = {Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT)
Japan Society for the Promotion of Science},
organization = {CNRST, Morocco},
organization = {RCN, Norway},
organization = {MEiN, Poland},
organization = {Fundacao para a Ciencia e a Tecnologia (FCT)},
organization = {MNE/IFA, Romania},
organization = {Ministry of Education, Science & Technological Development, Serbia},
organization = {MSSR, Slovakia},
organization = {Slovenian Research Agency - Slovenia},
organization = {MIZS, Slovenia},
organization = {Spanish Government},
organization = {Wallenberg Foundation, Sweden},
organization = {SERI, Switzerland},
organization = {Ministry of Science and Technology, Taiwan},
organization = {United States Department of Energy (DOE)},
organization = {National Science Foundation (NSF)},
organization = {BCKDF, Canada},
organization = {CANARIE, Canada},
organization = {Compute Canada, Canada},
organization = {Czech Republic Government	PRIMUS 21/SCI/017
UNCE SCI/013},
organization = {COST, European Union},
organization = {European Union (EU)
European Research Council (ERC)},
organization = {European Union (EU)
Marie Curie Actions},
organization = {Horizon 2020, European Union},
organization = {European Union (EU)
Marie Curie Actions},
organization = {Agence Nationale de la Recherche (ANR)},
organization = {German Research Foundation (DFG)},
organization = {Alexander von Humboldt Foundation},
organization = {Herakleitos programme - EU-ESF, Greece},
organization = {Thales Group},
organization = {Aristeia programme - EU-ESF, Greece},
organization = {Greek NSRF, Greece},
organization = {BSF-NSF, Israel},
organization = {MINERVA, Israel},
organization = {Norwegian Financial Mechanism 2014-2021, Norway},
organization = {NCN, Poland},
organization = {Polish National Agency for Academic Exchange (NAWA)},
organization = {La Caixa Banking Foundation, Spain},
organization = {CERCA Programme Generalitat de Catalunya, Spain},
organization = {PROMETEO Programme Generalitat Valenciana, Spain},
organization = {GenT Programme Generalitat Valenciana, Spain},
organization = {Goran Gustafssons Stiftelse, Sweden},
organization = {Royal Society},
organization = {Leverhulme Trust},
organization = {UK Research & Innovation (UKRI)
Science & Technology Facilities Council (STFC)},
organization = {TENMAK, Turkiye},
organization = {Canton of Geneva, Switzerland},
organization = {Canton of Bern, Switzerland},
organization = {Swiss National Science Foundation (SNSF)},
organization = {SRC, Sweden},
organization = {DSI/NRF, South Africa},
organization = {Netherlands Organization for Scientific Research (NWO)
Netherlands Government},
organization = {Benoziyo Center, Israel},
organization = {RGC, China},
organization = {GSRI, Greece},
organization = {HGF, Germany},
organization = {SRNSFG, Georgia},
organization = {Minciencias, Colombia},
organization = {Ministry of Science and Technology, China},
organization = {Chinese Academy of Sciences},
organization = {ANID, Chile},
organization = {CERN},
organization = {NRC, Canada},
publisher = {Springer Nature},
title = {Observation of four-top-quark production in the multilepton final state with the ATLAS detector},
doi = {10.1140/epjc/s10052-023-11573-0},
author = {Atlas Collaboration},
}