Search for new phenomena with top-quark pairs and large missing transverse momentum using 140 fb−1 of pp collision data at s = 13 TeV with the ATLAS detector

The ATLAS collaboration

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4 Scopus citations

Abstract

A search is conducted for new phenomena in events with a top quark pair and large missing transverse momentum, where the top quark pair is reconstructed in final states with one isolated electron or muon and multiple jets. The search is performed using the Large Hadron Collider proton-proton collision data sample at a centre-of-mass energy of s = 13 TeV recorded by the ATLAS detector that corresponds to an integrated luminosity of 140 fb−1. An analysis based on neural network classifiers is optimised to search for directly produced pairs of supersymmetric partners of the top quark (stop), and to search for spin-0 mediators, produced in association with a pair of top quarks, that decay into dark-matter particles. In the stop search, the analysis is designed to target models in which the mass difference between the stop and the neutralino from the stop decay is close to the top quark mass. This new search is combined with previously published searches in final states with different lepton multiplicities. No significant excess above the Standard Model background is observed, and limits at 95% confidence level are set. Models with neutralinos with masses up to 570 GeV are excluded, while for small neutralino masses models are excluded for stop masses up to 1230 GeV. Scalar (pseudoscalar) dark matter mediator masses as large as 350 (370) GeV are excluded when the coupling strengths of the mediator to Standard Model and dark-matter particles are both set to one. At lower mediator masses, models with production cross-sections as small as 0.15 (0.16) times the nominal predictions are excluded. Results of this search are also used to set constraints on effective four-fermion contact interactions between top quarks and neutrinos.

Original languageEnglish
Article number139
JournalJournal of High Energy Physics
Volume2024
Issue number3
DOIs
StatePublished - Mar 2024

Funding

FundersFunder number
BSF-NSF
Agence Nationale de la Recherche
Australian Research Council
La Caixa Banking Foundation
BMWFW
Centre National pour la Recherche Scientifique et Technique
Fundação para a Ciência e a Tecnologia
Cooperative Research Centres, Australian Government Department of Industry
Narodowe Centrum Nauki
National Science Foundation
CEA-DRF
Science and Technology Facilities Council
Horizon 2020, ICSC-NextGenerationEU
H2020 Marie Skłodowska-Curie Actions
Japan Society for the Promotion of Science
Nederlandse Organisatie voor Wetenschappelijk Onderzoek
Ministerio de Ciencia e Innovación
Ministry of Science and Technology, Taiwan
Israel Science Foundation
Wallenberg Foundation
Leverhulme Trust
PROMETEO
Staatssekretariat für Bildung, Forschung und Innovation
The Slovenian Research and Innovation Agency
Generalitat de Catalunya
Instituto Nazionale di Fisica Nucleare
Austrian Science Fund
Narodowa Agencja Wymiany Akademickiej
Agencia Nacional de Investigación y Desarrollo
Bundesministerium für Bildung und Forschung
Canada Foundation for Innovation
Helmholtz-Gemeinschaft
Danmarks Grundforskningsfond
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Canarie
Göran Gustafssons Stiftelser
MIZŠ
Deutsche Forschungsgemeinschaft
Ministarstvo Prosvete, Nauke i Tehnološkog Razvoja
U.S. Department of Energy
European Cooperation in Science and Technology
EU-ESF
RGC
Fundação de Amparo à Pesquisa do Estado de São Paulo
Institutul de Fizică Atomică
Natural Sciences and Engineering Research Council of Canada
Nella and Leon Benoziyo Center for Neurological Diseases, Weizmann Institute of Science
GenT Programmes Generalitat Valenciana, Spain
Irish Rugby Football Union
Cantons of Bern and Geneva
Chinese Academy of Sciences
Defence Science Institute
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
MNE
Agencia Nacional de Promoción Científica y Tecnológica
Royal Society
Minerva Foundation
European Research Council
National Research Foundation
European Regional Development Fund
CERN
Ministerstvo Školství, Mládeže a Tělovýchovy
National Research Council Canada
Alexander von Humboldt-Stiftung
Multiple Sclerosis Scientific Research Foundation
British Columbia Knowledge Development Fund
Ministry of Education, Culture, Sports, Science and Technology
National Natural Science Foundation of China
DNSRCIN2P3-CNRS
DRAC21/SCI/017
UNCESCI/013
Norwegian Financial Mechanism2014-2021

    Keywords

    • Hadron-Hadron Scattering

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