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Measurement of $B^+\to\tau^+\nu_\tau$ branching fraction with a hadronic tagging method at Belle II
Belle II Collaboration, I. Adachi, K. Adamczyk, H. Ahmed, Y. H. Ahn, H. Aihara, N. Akopov, M. Alhakami, A. Aloisio, N. Althubiti, M. Angelsmark, N. Anh Ky, D. M. Asner, H. Atmacan, V. Aushev, M. Aversano, R. Ayad, V. Babu, S. Bahinipati, S. Bahinipati, P. Bambade, Sw. Banerjee, Michael H. Bartl, J. Baudot, A. Baur, A. Beaubien, F. Becherer, J. V. Bennett, F. U. Bernlochner, V. Bertacchi, E. Bertholet, M. Bessner, S. Bettarini, B. Bhuyan, F. Bianchi, A. Bobrov, D. Bodrov, A. Bondar, J. Borah, A. Boschetti, A. Bożek, M. Bračko, P. Branchini, R. A. Briere, T. E. Browder, A. Budano, S. Bussino, Q. Campagna, M. Campajola, L. Cao, G. Casarosa, C. Cecchi, M. -C. Chang, P. Cheema, K. Chilikin, K. Chirapatpimol, H. -E. Cho, K. Cho, S. -J. Cho, S. -K. Choi, S. Choudhury, J. Cochran, L. Corona, J. X. Cui, E. De La Cruz–Burelo, S. A. De La Motte, G. De Nardo, G. De Pietro, R. de Sangro, M. Destefanis, S. Dey, A. Di Canto, J. Dingfelder, Z. Doležal, T. V. Dong, M. Dorigo, K. Dugic, G. Dujany, P. Ecker, D. Epifanov, T. Ferber, T. Fillinger, C. Finck, G. Finocchiaro, A. Fodor, F. Forti, B. G. Fulsom, A. Gabrielli, Lawrence M. Gartner, A. Gale, G. Gaudino, V. Gaur, A. Gellrich, G. Ghevondyan, D. Ghosh, H. Ghumaryan, G. Giakoustidis, R. Giordano, A. Giri, P. Gironella Gironell, B. Gobbo, R. Godang, O. Gogota, P. Goldenzweig, W. Gradl, E. Graziani, D. Greenwald, Z. Gruberová, Y. Guan, K. Gudkova, I. Haide, H. Hayashii, S. Hazra, C. Hearty, I. Heredia de la Cruz, T. Higuchi, M. Hoek, M. Hohmann, Richard T. Hoppe, P. Horak, C. -L. Hsu, Audrey Huang, T. Iijima, N. Ipsita, A. Ishikawa, R. Itoh, M. Iwasaki, P. Jackson, D. Jacobi, W. W. Jacobs, D. E. Jaffe, E. -J. Jang, Y. Jin, A. Johnson, K. K. Joo, H. Junkerkalefeld, J. Kandra, K. H. Kang, G. Karyan, T. Kawasaki, C. Ketter, C. Kiesling, D. Y. Kim, Jae-Young Kim, K. -H. Kim, H. Kindo, K. Kinoshita, P. Kodyš, T. Koga, S. Kohani, K. Kojima, A. Korobov, S. Korpar, E. Kovalenko, R. Kowalewski, P. Križan, P. Krokovny, T. Kuhr, D. Kumar, Rohit Kumar, K. Kumara, T. Kunigo, A. Kuzmin, Y. -J. Kwon, T. Lam, J. S. Lange, T. S. Lau, M. Laurenza, R. Leboucher, F. R. Le Diberder, M. J. Lee, P. Leo, L. K. Li, W. Z. Li, Y. Li, J. Libby, S. Lin, M. H. Liu, Q. Y. Liu, Z. Q. Liu, D. Liventsev, S. Longo, T. Lueck, C. Lyu, Yue Ma, C. Madaan, M. Maggiora, R. Maiti, G. Mancinelli, R. Manfredi, E. Manoni, M. Mantovano, D. Marcantonio, S. Marcello, C. Marinas, C. Martellini, A. Martens, T. Martinov, L. Massaccesi, M. Masuda, K. Matsuoka, S. K. Maurya, J. A. McKenna, D. Meleshko, M. Merola, C. Miller, M. Mirra, K. Miyabayashi, R. Mizuk, S. Mondal, S. Moneta, H. -G. Moser, I. Nakamura, M. Nakao, H. Nakazawa, Z. Natkaniec, A. Natochii, M. Nayak, M. Neu, M. Niiyama, S. Nishida, Shinichi Ogawa, R. Okubo, H. Ono, G. Pakhlova, S. Pardi, J. Park, K. Park, S. -H. Park, B. Paschen, S. Patra, S. Paul, T. K. Pedlar, I. Peruzzi, R. Peschke, L. E. Piilonen, T. Podobnik, S. Pokharel, C. Praz, S. Prell, E. Prencipe, M. T. Prim, S. Privalov, I. Prudiiev, H. Purwar, S. Raiz, K. Ravindran, J. U. Rehman, M. Reif, S. Reiter, M. Remnev, D. Ricalde Herrmann, I. Ripp-Baudot, G. Rizzo, S. H. Robertson, N. Rout, D. A. Sanders, L. Santelj, V. Savinov, B. Scavino, C. Schmitt, J. Schmitz, S. Schneider, C. Schwanda, Y. Seino, K. Senyo, M. E. Sevior, C. Sfienti, X. D. Shi, T. Shillington, J. -G. Shiu, D. Shtol, A. Sibidanov, F. Simon, J. B. Singh, J. Skorupa, R. J. Sobie, M. Sobotzik, A. Soffer, A. Sokolov, E. Solovieva, S. Spataro, B. Spruck, M. Starič, S. Stefkova, R. Stroili, Y. Sue, M. Sumihama, M. Takizawa, F. Tenchini, A. Thaller, O. Tittel, R. Tiwary, E. Torassa, K. Trabelsi, I. Tsaklidis, I. Ueda, T. Uglov, K. Unger, K. Uno, S. Uno, P. Urquijo, Y. Ushiroda, S. E. Vahsen, R. van Tonder, K. E. Varvell, M. Veronesi, A. Vinokurova, V. S. Vismaya, V. Vobbilisetti, R. Volpe, S. Wallner, M. -Z. Wang, A. Warburton, S. Watanuki, C. Wessel, E. Won, Xiaolong Xu, B. Yabsley, S. Yamada, W. B. Yan, S. B. Yang, J. Yelton, J. H. Yin, K. Yoshihara, C. Z. Yuan, Jing Yuan, L. Zani, F. Zeng, Boyang Zhang, V. Zhilich, Q. Zhou, L. Zhu, R. Žlebčík
Bibliographic record
VenueArXiv.org · 2025
Typepreprint
Languageen
FieldPhysics and Astronomy
TopicParticle physics theoretical and experimental studies
Canadian institutionsnot available
FundersInstitut National de Physique Nucléaire et de Physique des ParticulesAkademi Sains MalaysiaJapan Society for the Promotion of ScienceNatural Sciences and Engineering Research Council of CanadaKorea Research Environment Open NetworkNational Science and Technology CouncilCentro de Investigación y de Estudios Avanzados del Instituto Politécnico NacionalIstituto Nazionale di Fisica NucleareMinistry of Science and Higher Education of the Russian FederationNational Research University Higher School of EconomicsJavna Agencija za Raziskovalno Dejavnost RSKnut och Alice Wallenbergs StiftelseNational Research FoundationAustrian Science FundDeutsches Elektronen-SynchrotronThailand Center of Excellence in PhysicsGeneralitat ValencianaKing Saud UniversityU.S. Department of EnergyNational Natural Science Foundation of ChinaKorea Institute of Science and Technology InformationMinistry of Education, Culture, Sports, Science and TechnologyDeutsche ForschungsgemeinschaftMax-Planck-GesellschaftNational Research Foundation of UkraineGrantová Agentura České RepublikyAlexander von Humboldt-StiftungBundesministerium für Bildung, Wissenschaft und ForschungMinistry of Education and Science of UkraineVietnam Academy of Science and TechnologyNatural Science Foundation of Shandong ProvinceCompute CanadaUniversity of TabukNational Science FoundationKorea Institute of Science and TechnologyBundesministerium für Bildung und ForschungCanarieTürkiye Bilimsel ve Teknolojik Araştırma KurumuAgence Nationale de la RechercheGrantová Agentura, Univerzita KarlovaCentre National de la Recherche ScientifiqueUniverzita Karlova v PrazeEuropean Commission
KeywordsBranching (polymer chemistry)HadronPhysicsParticle physicsBranching fractionNuclear physicsChemistry
Abstract
We present a measurement of the branching fraction of $B^+\to\tau^+\nu_\tau$ decays using $(387\pm6)\times 10^6$$\Upsilon(4S)$ collected between 2019 and 2022 with the Belle II detector at the SuperKEKB $e^+e^-$ collider. We reconstruct the accompanying $B^-$ meson using the hadronic tagging method, while $B^+\to\tau^+\nu_\tau$ candidates are identified in the recoil. We find evidence for $B^+\to\tau^+\nu_\tau$ decays at 3.0 standard deviations, including systematic uncertainties. The measured branching fraction is $\mathcal{B}(B^+\to\tau^+\nu_\tau) = [1.24 \pm 0.41 (\text{stat.}) \pm 0.19 (\text{syst.})] \times 10^{-4}$.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.001
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.004
Threshold uncertainty score0.009
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
Opus teacher head0.032
GPT teacher head0.305
Teacher spread0.273 · how far apart the two teachers sit on this one work
Validation status
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
The models applied no category: nothing in the taxonomy fit this work.
Study designBench or experimental
Domainnot available
GenreEmpirical
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".
Quick stats
Citations0
Published2025
Admission routes1
Has abstractyes