Search for Bs0 → ℓ∓ τ± with the semi-leptonic tagging method at Belle

L Nayak; S Nishida; A Giri; I Adachi; H Aihara; DM Asner; H Atmacan; V Aulchenko; T Aushev; R Ayad; V Babu; S Bahinipati; S Banerjee; M Bauer; P Behera; K Belous; J Bennett; M Bessner; B Bhuyan; D Biswas; D Bodrov; J Borah; A Bozek; M Bračko; P Branchini; TE Browder; A Budano; M Campajola; D Červenkov; MC Chang; BG Cheon; K Chilikin; HE Cho; K Cho; SK Choi; Y Choi; S Choudhury; D Cinabro; J Cochran; S Das; N Dash; G De Nardo; G De Pietro; R Dhamija; F Di Capua; J Dingfelder; Z Doležal; TV Dong; D Dossett; S Dubey; D Epifanov; T Ferber; D Ferlewicz; BG Fulsom; R Garg; V Gaur; P Goldenzweig; E Graziani; T Gu; Y Guan; S Halder; T Hara; K Hayasaka; H Hayashii; MT Hedges; D Herrmann; WS Hou; CL Hsu; T Iijima; K Inami; G Inguglia; N Ipsita; A Ishikawa; R Itoh; M Iwasaki; WW Jacobs; EJ Jang; S Jia; Y Jin; KK Joo; AB Kaliyar; T Kawasaki; C Kiesling; CH Kim; DY Kim; KH Kim; YK Kim; K Kinoshita; P Kodyš; T Konno; A Korobov; S Korpar; E Kovalenko; P Križan; P Krokovny; T Kuhr; M Kumar; R Kumar; K Kumara; A Kuzmin

Journal article

Search for Bs0 → ℓ∓ τ± with the semi-leptonic tagging method at Belle

L Nayak, S Nishida, A Giri, I Adachi, H Aihara, DM Asner, H Atmacan, V Aulchenko, T Aushev, R Ayad, V Babu, S Bahinipati, S Banerjee, M Bauer, P Behera, K Belous, J Bennett, M Bessner, B Bhuyan, D Biswas Show all

Journal of High Energy Physics | SPRINGER | Published : 2023

DOI: 10.1007/JHEP08(2023)178

Abstract

We present a search for the lepton-flavor-violating decays Bs0 → ℓ∓ τ±, where ℓ = e, μ, using the full data sample of 121 fb−1 collected at the Υ(5S) resonance with the Belle detector at the KEKB asymmetric-energy e+ e− collider. We use Bs0B¯s0 events in which one Bs0 meson is reconstructed in a semileptonic decay mode and the other in the signal mode. We find no evidence for Bs0 → ℓ∓ τ± decays and set upper limits on their branching fractions at 90% confidence level as B (Bs0 → e∓ τ±) < 14 × 10−4 and B (Bs0 → μ∓ τ±) < 7.3 × 10−4. Our result represents the first upper limit on the Bs0 → e∓ τ± decay rate. [Figure not available: see fulltext.]

University of Melbourne Researchers

Martin Sevior Author

Phillip Urquijo Author

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Funding Acknowledgements

This work, based on data collected using the Belle detector, which was operated until June 2010, was supported by the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan, the Japan Society for the Promotion of Science (JSPS), and the Tau-Lepton Physics Research Center of Nagoya University; the Australian Research Council including grants DP180102629, DP170102389, DP170102204, DE220100462, DP150103061, FT130100303; Austrian Federal Ministry of Education, Science and Research (FWF) and FWF Austrian Science Fund No. P 31361-N36; the National Natural Science Foundation of China under Contracts No. 11675166, No. 11705209; No. 11975076; No. 12135005; No. 12175041; No. 12161141008; Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS), Grant No. QYZDJ-SSW-SLH011; the Ministry of Education, Youth and Sports of the Czech Republic under Contract No. LTT17020; the Czech Science Foundation Grant No. 22-18469S; Horizon 2020 ERC Advanced Grant No. 884719 and ERC Starting Grant No. 947006 "InterLeptons" (European Union); the Carl Zeiss Foundation, the Deutsche Forschungsgemeinschaft, the Excellence Cluster Universe, and the VolkswagenStiftung; the Department of Atomic Energy (Project Identification No. RTI 4002) and the Department of Science and Technology of India; the Istituto Nazionale di Fisica Nucleare of Italy; National Research Foundation (NRF) of Korea Grant Nos. 2016R1D1A1B02012900, 2018R1A2B3003643, 2018R1A6A1A06024970, RS202200197659, 2019R1I1A3A01058933, 2021R1A6A1A03043957, 2021R1F1A1060423, 2021R1F1A1064008, 2022R1A2C1003993; Radiation Science Research Institute, Foreign Large-size Research Facility Application Supporting project, the Global Science Experimental Data Hub Center of the Korea Institute of Science and Technology Information and KREONET/GLORIAD; the Polish Ministry of Science and Higher Education and the National Science Center; the Ministry of Science and Higher Education of the Russian Federation, Agreement 14.W03.31.0026, and the HSE University Basic Research Program, Moscow; University of Tabuk research grants S-1440-0321, S-0256-1438, and S-0280-1439 (Saudi Arabia); the Slovenian Research Agency Grant Nos. J1-9124 and P1-0135; Ikerbasque, Basque Foundation for Science, Spain; the Swiss National Science Foundation; the Ministry of Education and the Ministry of Science and Technology of Taiwan; and the United States Department of Energy and the National Science Foundation. These acknowledgements are not to be interpreted as an endorsement of any statement made by any of our institutes, funding agencies, governments, or their representatives. We thank the KEKB group for the excellent operation of the accelerator; the KEK cryogenics group for the efficient operation of the solenoid; and the KEK computer group and the Pacific Northwest National Laboratory (PNNL) Environmental Molecular Sciences Laboratory (EMSL) computing group for strong computing support; and the National Institute of Informatics, and Science Information NETwork 6 (SINET6) for valuable network support. S.N. is supported by JSPS KAKENHI grant JP17K05474.