CERN Accelerating science

Article
Report number arXiv:2010.02566 ; CERN-EP-2020-163
Title Search for charged-lepton-flavour violation in Z-boson decays with the ATLAS detector
Related titleCharged-lepton-flavour violation at the LHC: a search for Zeτ/μτ decays with the ATLAS detector
Author(s) ATLAS Collaboration  Visa alla 2952 författare
Corporate Author(s) ATLAS Collaboration
Publication 2021-07-01
Imprint 06 Oct 2020
Number of pages 24
Note All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2018-36/
In: Nature Phys. 17 (2021) 819
DOI 10.1038/s41567-021-01225-z (publication)
Subject category Particle Physics - Experiment
Accelerator/Facility, Experiment CERN LHC ; ATLAS
Free keywords exotics ; conservation law tests ; experimental results
Abstract Leptons with essentially the same properties apart from their mass are grouped into three families (or flavours). The number of leptons of each flavour is conserved in interactions, but this is not imposed by fundamental principles. Since the formulation of the standard model of particle physics, the observation of flavour oscillations among neutrinos has shown that lepton flavour is not conserved in neutrino weak interactions. So far, there has been no experimental evidence that this also occurs in interactions between charged leptons. Such an observation would be a sign for undiscovered particles or a yet unknown type of interaction. Here, the ATLAS experiment at the Large Hadron Collider at CERN reports a constraint on lepton-flavour-violating effects in weak interactions, searching for Z-boson decays into a τ lepton and another lepton of different flavour with opposite electric charge. The branching fractions for these decays are measured to be less than 8.1×106 (eτ) and 9.5×106 (μτ) at 95\% confidence level using 139 fb1 of proton--proton collision data at a centre-of-mass energy s=13 TeV and 20.3 fb1 at s=8 TeV. These results supersede the limits from the Large Electron–Positron Collider experiments conducted more than two decades ago.
Copyright/License preprint: © 2020-2025 CERN (License: CC-BY-4.0)
publication: © 2021-2025 The Author(s) (License: CC-BY-4.0)



Corresponding record in: Inspire
Email contact: tatjana.lenz@cern.ch


 Journalen skapades 2020-10-06, och modifierades senast 2024-12-13


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