Search for τ− → μ−μ+μ− decays at the LHCb experiment with Run 2 data

Journal of High Energy Physics 2026 Open access

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Authors: R. Aaij, A. S. W. Abdelmotteleb, Carlos Abellán Beteta, C. Abellán Beteta, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, H. Afsharnia, C. Aidala, Z. Ajaltouni
+88 more S. Akar, K. Carvalho Akiba, Muzammil Akthar, P. Albicocco, J. Albrecht, R. Aleksiejūnas, F. Alessio, P. Álvarez Cartelle, R. Amalric, S. Amato, S. Amato, Y. Amhis, L. An, L. An, M. Andersson, P. Andreola, M. Andreotti, Sergio Andres Estrada, Alessia Anelli, D. Ao, C. Arata, F. Archilli, Zaratsyan Areg, Marco Argenton, S. Arguedas Cuendis, Lisa Arnone, A. Artamonov, M. Artuso, E. Aslanides, R. Ataíde Da Silva, M. Atzeni, B. Audurier, Juliette Authier, D. Bacher, I. Bachiller, S. Bachmann, Marie Bachmayer, John J Back, P. Baladrón Rodríguez, V. Balagura, A Balboni, W. Baldini, Zachary Baldwin, Luca Balzani, H. -R. Bao, J. Baptista de Souza Leite, C. Barbero Pretel, M. Barbetti, I. R. Barbosa, Roger John Barlow, Mikhail Barnyakov, S. Barsuk, William James Barter, J. Bartz, Saliha Bashir, B. Batsukh, Piera Battista, Ali Bavarchee, A. Bay, M. Becker, M. Becker, F. Bedeschi, I. Bediaga, Noah Albin Behling, S. Belin, Alberto Bellavista, K. Belous, I. Belov, I. Belyaev, E. Ben-Haim, G. Benane, G Bencivenni, Alexander Berezhnoy, R. Bernet, R. Bernet, A. Bertolin, F. Betti, J. Bex, Oleg Bezshyyko, Senjuti Bhattacharya, M. S. Bieker, N. V. Biesuz, Alice Biolchini, M. Birch, F. C. R. Bishop, A. Bitadze, A. Bizzeti, T. Blake
DOI: 10.1007/jhep09(2026)069
Cited by: 0

Abstract

A bstract A search for the lepton-flavour-violating decay τ − → μ − μ + μ − is carried out using data collected by the LHCb experiment between 2016 and 2018 in proton-proton collisions at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb − 1 . An upper limit of 1 . 9 (2 . 3) × 10 − 8 is set at the 90% (95%) confidence level on the branching fraction of the decay.

Fields of Study & Subjects

Particle physics theoretical and experimental studies Particle Detector Development and Performance Quantum Chromodynamics and Particle Interactions

Publication details

Journal / source
Journal of High Energy Physics
Volume
2026
Issue
9
Pages
069
Publication date
4 September 2026
Language
EN