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Image of Hannah Herde in front of Fysicum captured by Johan Joelsson

Hannah Herde

Interests: Higgs physics • dark matter searches • solid state tracking detectors • track reconstruction • active teaching methods • digital art • improv

Image of Hannah Herde in front of Fysicum captured by Johan Joelsson

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

Author

  • G. Aad
  • T.P.A. Åkesson
  • E.E. Corrigan
  • C. Doglioni
  • P.A. Ekman
  • J. Geisen
  • V. Hedberg
  • H. Herde
  • G. Jarlskog
  • B. Konya
  • E. Lytken
  • J.U. Mjörnmark
  • R. Poettgen
  • N.D. Simpson
  • E. Skorda
  • O. Smirnova
  • L. Zwalinski
Show all

Summary, in English

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 → ℓνℓ ντ) 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. [Figure not available: see fulltext.]. © 2023, The Author(s).

Department/s

  • Particle and nuclear physics
  • eSSENCE: The e-Science Collaboration

Publishing year

2023

Language

English

Publication/Series

Journal of High Energy Physics

Volume

2023

Issue

7

Document type

Journal article

Publisher

Springer

Topic

  • Subatomic Physics

Keywords

  • Hadron-Hadron Scattering

Status

Published

ISBN/ISSN/Other

  • ISSN: 1029-8479