Searches for lepton-flavour-violating decays of the Higgs boson into etau and mutau in √s = 13 TeV pp collisions with the ATLAS detector

This paper presents direct searches for lepton flavour violation in Higgs boson decays, H → eτ and H → μτ, performed using data collected with the ATLAS detector at the LHC. The searches are based on a data sample of proton-proton collisions at a centre-of-mass energy √s = 13 TeV, corresponding to a...

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Main Authors: Aad, Georges (Author) , Baltes, Lisa Marie (Author) , Bartels, Falk (Author) , Castillo, Florencia Luciana (Author) , Czurylo, Marta (Author) , Rio, Fernando del (Author) , Dittmeier, Sebastian (Author) , Dunford, Monica (Author) , Franchino, Silvia (Author) , Junkermann, Thomas (Author) , Klassen, Martin (Author) , Mkrtchyan, Tigran (Author) , Ott, Philipp (Author) , Rassloff, Damir Fabrice (Author) , Rodriguez Bosca, Sergi (Author) , Sauer, Christof (Author) , Schöning, André (Author) , Schultz-Coulon, Hans-Christian (Author) , Sothilingam, Varsiha (Author) , Stamen, Rainer (Author) , Starovoitov, Pavel (Author) , Vigani, Luigi (Author) , Weber, Sebastian (Author) , Wessels, Martin (Author) , Zinßer, Joachim (Author)
Corporate Author: ATLAS Collaboration (Author)
Format: Article (Journal)
Language:English
Published: 2023
In: Journal of high energy physics
Year: 2023, Issue: 7, Pages: 1-74
ISSN:1029-8479
DOI:10.1007/JHEP07(2023)166
Online Access:Verlag, kostenfrei, Volltext: https://doi.org/10.1007/JHEP07(2023)166
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Author Notes:The ATLAS collaboration*
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Summary:This paper presents direct searches for lepton flavour violation in Higgs boson decays, H → eτ and H → μτ, performed using data collected with the ATLAS detector at the LHC. The searches are based on a data sample of proton-proton collisions at a centre-of-mass energy √s = 13 TeV, corresponding to an integrated luminosity of 138 fb−1. Leptonic (τ → ℓνℓντ) and hadronic (τ → hadrons ντ) decays of the τ-lepton are considered. Two background estimation techniques are employed: the MC-template method, based on data-corrected simulation samples, and the Symmetry method, based on exploiting the symmetry between electrons and muons in the Standard Model backgrounds. No significant excess of events is observed and the results are interpreted as upper limits on lepton-flavour-violating branching ratios of the Higgs boson. The observed (expected) upper limits set on the branching ratios at 95% confidence level, B(H → eτ) < 0.20% (0.12%) and B(H → μτ ) < 0.18% (0.09%), are obtained with the MC-template method from a simultaneous measurement of potential H → eτ and H → μτ signals. The best-fit branching ratio difference, B(H → μτ) → B(H → eτ), measured with the Symmetry method in the channel where the τ-lepton decays to leptons, is (0.25 ± 0.10)%, compatible with a value of zero within 2.5σ.
Item Description:Veröffentlicht: 21. Juli 2023
*The ATLAS collaboration: G. Aad, L.M. Baltes, F. Bartels, F.L. Castillo, M.M. Czurylo, F. Del Rio, S.J. Dittmeier, M. Dunford, S. Franchino, T. Junkermann, M. Klassen, T. Mkrtchyan, P.S. Ott, D.F. Rassloff, S. Rodriguez Bosca, C. Sauer, A. Schoening, H.-C. Schultz-Coulon, V. Sothilingam, P. Starovoitov, L. Vigani, S.M. Weber, M. Wessels, J. Zinsser [und sehr viele weitere Personen]
Im Titel sind "tau" und "mu" als griechische Buchstaben dargestellt
Im Titel steht der Buchstabe "s" unter dem Wurzelsymbol
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Physical Description:Online Resource
ISSN:1029-8479
DOI:10.1007/JHEP07(2023)166