Search for flavour-changing neutral-current interactions of a top quark and a gluon in pp collisions at √s=13 TeV with the ATLAS detector

A search is presented for the production of a single top quark via left-handed flavour-changing neutral-current (FCNC) interactions of a top quark, a gluon and an up or charm quark. Two production processes are considered: u+g→t and c+g→t. The analysis is based on proton–proton collision data taken...

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Hauptverfasser: Aad, Georges (VerfasserIn) , Baltes, Lisa Marie (VerfasserIn) , Bartels, Falk (VerfasserIn) , Castillo, Florencia Luciana (VerfasserIn) , Czurylo, Marta (VerfasserIn) , Dittmeier, Sebastian (VerfasserIn) , Dunford, Monica (VerfasserIn) , Franchino, Silvia (VerfasserIn) , Klassen, Martin (VerfasserIn) , Krishnan, Anjali (VerfasserIn) , Mkrtchyan, Tigran (VerfasserIn) , Napolitano, Fabrizio (VerfasserIn) , Ott, Philipp (VerfasserIn) , Rassloff, Damir Fabrice (VerfasserIn) , Rodriguez Bosca, Sergi (VerfasserIn) , Sauer, Christof (VerfasserIn) , Schöning, André (VerfasserIn) , Schultz-Coulon, Hans-Christian (VerfasserIn) , Spieker, Thomas (VerfasserIn) , Stamen, Rainer (VerfasserIn) , Starovoitov, Pavel (VerfasserIn) , Vigani, Luigi (VerfasserIn) , Weber, Sebastian (VerfasserIn) , Wessels, Martin (VerfasserIn) , Yue, Xiaoguang (VerfasserIn) , Zinßer, Joachim (VerfasserIn)
Körperschaft: ATLAS Collaboration (VerfasserIn)
Dokumenttyp: Article (Journal)
Sprache:Englisch
Veröffentlicht: 19 April 2022
In: The European physical journal. C, Particles and fields
Year: 2022, Jahrgang: 82, Heft: 4, Pages: 1-35
ISSN:1434-6052
DOI:10.1140/epjc/s10052-022-10182-7
Online-Zugang:Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1140/epjc/s10052-022-10182-7
Volltext
Verfasserangaben:ATLAS Collaboration*
Beschreibung
Zusammenfassung:A search is presented for the production of a single top quark via left-handed flavour-changing neutral-current (FCNC) interactions of a top quark, a gluon and an up or charm quark. Two production processes are considered: u+g→t and c+g→t. The analysis is based on proton–proton collision data taken at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. The data set corresponds to an integrated luminosity of 139 fb−1. Events with exactly one electron or muon, exactly one b-tagged jet and missing transverse momentum are selected, resembling the decay products of a singly produced top quark. Neural networks based on kinematic variables differentiate between events from the two signal processes and events from background processes. The measured data are consistent with the background-only hypothesis, and limits are set on the production cross-sections of the signal processes: σ(u+g→t)×B(t→Wb)×B(W→ℓν)<3.0pb and σ(c+g→t)×B(t→Wb)×B(W→ℓν)<4.7pb at the 95% confidence level, with B(W→ℓν)=0.325 being the sum of branching ratios of all three leptonic decay modes of the W boson. Based on the framework of an effective field theory, the cross-section limits are translated into limits on the strengths of the tug and tcg couplings occurring in the theory: |CutuG|/Λ2<0.057TeV−2 and |CctuG|/Λ2<0.14TeV−2. These bounds correspond to limits on the branching ratios of FCNC-induced top-quark decays: B(t→u+g)<0.61×10−4 and B(t→c+g)<3.7×10−4.
Beschreibung:Im Titel steht der Buchstabe s unter dem Wurzelsymbol
ATLAS Collaboration*: G. Aad, L.M. Baltes, F. Bartels, F.L. Castillo, M.M. Czurylo, S.J. Dittmeier, M. Dunford, S. Franchino, M. Klassen, A. Krishnan, T. Mkrtchyan, F. Napolitano, P.S. Ott, D.F. Rassloff, S. Rodriguez Bosca, C. Sauer, A. Schoening, H-C. Schultz-Coulon, T.M. Spieker, R. Stamen, P. Starovoitov, L. Vigani, S.M. Weber, M. Wessels, X. Yue, J. Zinsser [und viele weitere]
Gesehen am 25.10.2022
Beschreibung:Online Resource
ISSN:1434-6052
DOI:10.1140/epjc/s10052-022-10182-7