Searches for Charged-Lepton-Flavor Violation in χ b J ( 1 P ) Decays

Physical Review Letters 2026 Open access

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Authors: M. Abumusabh, Ichiro Adachi, :, L. Aggarwal, Hossain Ahmed, Y. H. Ahn, H. Aihara, N. Z. Akopov, Saleh A. Alghamdi, M. Alhakami, A. Aloisio, N. Althubiti
+88 more K. R. Amos, Martin Angelsmark, N. Anh Ky, C. Antonioli, David M. Asner, H. Atmacan, T. Aushev, Rachid Ayad, V. Babu, H. Bae, N. K. Baghel, S. Bahinipati, Philip Bambade, Sw. Banerjee, M. Barrett, M. Bartl, J. Baudot, A. Baur, A. Beaubien, F. Becherer, Jürgen Becker, J. V. Bennett, F. U. Bernlochner, V. Bertacchi, M. Bertemes, E. Bertholet, M. Bessner, S. Bettarini, Vishal Bhardwaj, Fabrizio Bianchi, T. Bilka, D. Biswas, A.V. Bobrov, D. Bodrov, A. Bondar, G. Bonvicini, J. Borah, A. Boschetti, Andrzej Bozek, M. Bračko, P. Branchini, Roy A. Briere, Thomas E. Browder, A. Budano, S. Bussino, Q. Campagna, M. Campajola, L. Cao, G. Casarosa, Claudia Cecchi A, M.-C. Chang, P. Chang, P. Cheema, L. Chen, B. G. Cheon, C. Madaan, Hridey Chetri, K. Chilikin, K. Chirapatpimol, H. E. Cho, K. Cho, S.-J. Cho, H. -E. Cho, K. Cho, Sourabh Chutia, J. Cochran, J. A. Colorado-Caicedo, I. Consigny, L. Corona, J. X. Cui, E. De La Cruz–Burelo, S. A. De La Motte, Guglielmo De Nardo, G. De Pietro, Riccardo de Sangro, Marco Giovanni Maria Destefanis, S. Dey, R. Dhayal, Angelo Di Canto, J. Dingfelder, Z. Doležal, I. Domínguez Jiménez, T. V. Dong, X. Dong, G. Dujany, P. Ecker, D. Epifanov, J. Eppelt
DOI: 10.1103/1rj5-2wvr
Cited by: 0
References: 40

Abstract

We report the first searches for charged-lepton-flavor violation in decays of χ_{bJ}(1P) (J=0, 1, and 2) to a pair of charged leptons using 158 million ϒ(2S) decays collected with the Belle detector in e^{+}e^{-} collisions at the KEKB collider. No significant signal is observed, and we set upper limits on the branching fractions for χ_{bJ}(1P) decays to e^{±}μ^{∓} at the level of 10^{-6} and to e^{±}τ^{∓} or μ^{±}τ^{∓} at the level of 10^{-5}. Limits on χ_{b0}(1P) decays are translated into bounds on the corresponding Wilson coefficients of scalar operators that mediate charged-lepton-flavor violation.

Fields of Study & Subjects

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

Publication details

Journal / source
Physical Review Letters
Volume
137
Issue
7
Pages
071803–071803
Publication date
6 July 2026
Language
EN