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Observation of four-top-quark production in the multilepton final state with the ATLAS detector

Aad, G ; Åkesson, Torsten LU orcid ; Doglioni, Caterina LU ; Ekman, Alexander LU orcid ; Hedberg, Vincent LU ; Herde, Hannah LU orcid ; Konya, Balazs LU ; Lytken, Else LU orcid ; Pöttgen, Ruth LU orcid and Simpson, Nathan Daniel LU , et al. (2023) In European Physical Journal C. Particles and Fields 83(6).
Abstract
This paper presents the observation of four-top-quark (tt¯ tt¯) 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 TeV collected 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 the measured tt¯ tt¯ signal with respect to the standard model (SM) background-only hypothesis is 6.1 (4.3) standard deviations. The tt¯ tt¯ production... (More)
This paper presents the observation of four-top-quark (tt¯ tt¯) 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 TeV collected 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 the measured tt¯ tt¯ signal with respect to the standard model (SM) background-only hypothesis is 6.1 (4.3) standard deviations. The tt¯ tt¯ production cross section is measured to be 22.5-5.5+6.6 fb, consistent with the SM prediction 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 tt¯ tt¯ production. © 2023, The Author(s). (Less)
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Contribution to journal
publication status
published
subject
keywords
Elementary particles, Statistics, A-center, ATLAS detectors, Final state, Integrated luminosity, Production cross section, Proton proton collisions, Quark production, Standard deviation, The standard model, Top quarks, Tellurium compounds
in
European Physical Journal C. Particles and Fields
volume
83
issue
6
article number
496
publisher
Springer Nature
external identifiers
  • scopus:85164151361
ISSN
1434-6044
DOI
10.1140/epjc/s10052-023-11573-0
language
English
LU publication?
yes
id
0739173d-99df-4472-9c97-64f1f9d32ab6
date added to LUP
2025-10-16 13:02:04
date last changed
2025-10-17 10:39:13
@article{0739173d-99df-4472-9c97-64f1f9d32ab6,
  abstract     = {{This paper presents the observation of four-top-quark (tt¯ tt¯) 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 TeV collected 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 the measured tt¯ tt¯ signal with respect to the standard model (SM) background-only hypothesis is 6.1 (4.3) standard deviations. The tt¯ tt¯ production cross section is measured to be 22.5-5.5+6.6 fb, consistent with the SM prediction 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 tt¯ tt¯ production. © 2023, The Author(s).}},
  author       = {{Aad, G and Åkesson, Torsten and Doglioni, Caterina and Ekman, Alexander and Hedberg, Vincent and Herde, Hannah and Konya, Balazs and Lytken, Else and Pöttgen, Ruth and Simpson, Nathan Daniel and Smirnova, Oxana and Zwalinski, L.}},
  issn         = {{1434-6044}},
  keywords     = {{Elementary particles; Statistics; A-center; ATLAS detectors; Final state; Integrated luminosity; Production cross section; Proton proton collisions; Quark production; Standard deviation; The standard model; Top quarks; Tellurium compounds}},
  language     = {{eng}},
  number       = {{6}},
  publisher    = {{Springer Nature}},
  series       = {{European Physical Journal C. Particles and Fields}},
  title        = {{Observation of four-top-quark production in the multilepton final state with the ATLAS detector}},
  url          = {{http://dx.doi.org/10.1140/epjc/s10052-023-11573-0}},
  doi          = {{10.1140/epjc/s10052-023-11573-0}},
  volume       = {{83}},
  year         = {{2023}},
}