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Search for lepton-flavor-violating $τ^- \to \ell^-ϕ$ decays in 2019-2021 Belle II data
Belle II Collaboration, F. Abudinén, I. Adachi, K. Adamczyk, L. Aggarwal, P. Ahlburg, H. Ahmed, J. K. Ahn, H. Aihara, Н. Акопов, A. Aloisio, L. Andricek, N. Anh Ky, D. M. Asner, H. Atmacan, V. Aulchenko, T. Aushev, V. Aushev, M. Aversano, V. Babu, S. Bacher, H. Bae, S. Bahinipati, A. M. Bakich, P. Bambade, Sw. Banerjee, S. Bansal, M. D. Barrett, G. Batignani, J. Baudot, M. Bauer, A. Baur, A. Beaulieu, Jürgen Becker, P. K. Behera, J. V. Bennett, E. Bernieri, F. U. Bernlochner, V. Bertacchi, M. Bertemes, E. Bertholet, M. Bessner, S. Bettarini, V. Bhardwaj, B. Bhuyan, F. Bianchi, T. Bilka, S. Bilokin, D. Biswas, A. Bobrov, D. Bodrov, A. E. Bolz, A. Bondar, G. Bonvicini, J. Borah, A. Bożek, M. Bračko, P. Branchini, R. A. Briere, T. E. Browder, D. N. Brown, A. Budano, S. Bussino, M. Campajola, L. Cao, G. Casarosa, C. Cecchi, J. Cerasoli, D. Červenkov, M. -C. Chang, P. Chang, R. Cheaib, P. Cheema, V. Chekelian, C. Chen, Y. Q. Chen, Y. -T. Chen, B. G. Cheon, K. Chilikin, K. Chirapatpimol, H. -E. Cho, K. Cho, S. -J. Cho, S.-K. Choi, S. Choudhury, D. Cinabro, J. Cochran, L. Corona, L. Cremaldi, S. Cunliffe, T. Czank, S. Das, F. Dattola, E. De La Cruz–Burelo, S. A. De La Motte, G. de Marino, G. De Nardo, M. De Nuccio, G. De Pietro, R. de Sangro, B. Deschamps, M. Destefanis, S. Dey, A. De Yta-Hernandez, R. Dhamija, A. Di Canto, F. Di Capua, J. Dingfelder, Z. Doležal, I. Domínguez Jiménez, T. V. Dong, M. Dorigo, K. Dort, D. Dossett, S. Dreyer, S. Dubey, S. Duell, G. Dujany, P. Ecker, M. Eliachevitch, D. Epifanov, P. Feichtinger, T. Ferber, D. Ferlewicz, T. Fillinger, C. Finck, G. Finocchiaro, P. Fischer, K. T. Flood, A. Fodor, F. Forti, A. Frey, M. Friedl, B. G. Fulsom, A. Gabrielli, N. Gabyshev, E. Ganiev, M. Garcia-Hernandez, Renu Garg, A. Garmash, G. Gaudino, V. Gaur, A. Gaz, U. Gebauer, A. Gellrich, G. Ghevondyan, Dilip Ghosh, G. Giakoustidis, R. Giordano, A. Giri, A. Glazov, B. Gobbo, R. Godang, P. Goldenzweig, B. Golob, G. H. Gong, P. Grace, W. Gradl, M. Graf-Schreiber, T. Grammatico, S. Granderath, E. Graziani, D. Greenwald, Z. Gruberová, T. Gu, Y. Guan, K. Gudkova, C. Hadjivasiliou, S. Halder, Y. L. Han, K. Hara, Takanori Hara, O. Hartbrich, K. Hayasaka, H. Hayashii, S. Hazra, C. Hearty, M. T. Hedges, I. Heredia-De La Cruz, M. Hernández Villanueva, A. Hershenhorn, T. Higuchi, E. Hill, H. Hirata, M. Hoek, M. Hohmann, T. Hotta, C.-L. Hsu, K. Huang, T. Humair, T. Iijima, K. Inami, G. Inguglia, N. Ipsita, J. Irakkathil Jabbar, A. Ishikawa, S. Ito, R. Itoh, M. Iwasaki, S. Iwata, P. Jackson, W. W. Jacobs, D. E. Jaffe, E. -J. Jang, H. B. Jeon, Q. P. Ji, S. Jia, Y. Jin, K. K. Joo, H. Junkerkalefeld, І. Каденко, H. Kakuno, M. Kaleta, D. Kalita, A. B. Kaliyar, J. Kandra, K. H. Kang, S. Kang, P. Kapusta, Robert Karl, G. Karyan, Yuko Kato, T. Kawasaki, C. Ketter, C. Kiesling, C. -H. Kim, D. Y. Kim, H.J. Kim, K. -H. Kim, Y. -K. Kim, Y.J. Kim, T. D. Kimmel, H. Kindo, K. Kinoshita, C. Kleinwort, T. Koga, S. Kohani, K. Kojima, T. Konno, A. Korobov, S. Korpar, E. Kovalenko, R. Kowalewski, T. M. G. Kraetzschmar, P. Križan, J. F. Krohn, P. Krokovny, W. Kuehn, T. Kuhr, J. Kumar, M. Kumar, R. Kumar, K. Kumara, T. Kumita, T. Kunigo, S. Kurz, A. Kuzmin, P. Kvasnička, Y.-J. Kwon, S. Lacaprara, Y-T Lai, C. La Licata, K. Lalwani, T. Lam, L. Lanceri, J. S. Lange, M. Laurenza, K. Lautenbach, P. Laycock, R. Leboucher, F. R. Le Diberder, S. C. Lee, P. Leitl, D. Levit, P. Lewis, C. Li, L. K. Li, S. X. Li, Y. B. Li, J. Libby, K. Lieret, J. Lin, Z. Liptak, Q. Y. Liu, Z. A. Liu, Z. Q. Liu, D. Liventsev, S. Longo, A. Lozar, T. Lueck, T. Luo, C. Lyu, Yueyun Ma, M. Maggiora, S. P. Maharana, R. Maiti, S. Maity, R. Manfredi, E. Manoni, A. C. Manthei, D. Marcantonio, S. Marcello, C. Mariñas, L. Martel, C. Martellini, A. Martini, T. Martinov, L. Massaccesi, M. Masuda, Tatsuma D. Matsuda, K. Matsuoka, D. Matvienko, S. K. Maurya, J. A. McKenna, J. McNeil, F. Meggendorfer, F. Meier, M. Merola, F. Metzner, M. Milesi, C. Miller, K. Miyabayashi, H. Miyake, H. Miyata, R. Mizuk, G. B. Mohanty, N. Molina-Gonzalez, S. Mondal, S. Moneta, H. K. Moon, H. -G. Moser, M. Mrvar, T. Müller, R. Mussa, I. Nakamura, K. R. Nakamura, E. Nakano, M. Nakao, Hiroyuki Nakayama, H. Nakazawa, Y. Nakazawa, M. Naruki, D. Narwal, Z. Natkaniec, A. Natochii, L. Nayak, M. Nayak, G. Nazaryan, C. Niebuhr, M. Niiyama, J. Ninkovic, N. K. Nisar, S. Nishida, K. Nishimura, M. H. A. Nouxman, K. Ogawa, S. L. Olsen, Y. Onishchuk, H. Ono, Y. Onuki, P. Oskin, E. R. Oxford, H. Ozaki, P. Pakhlov, G. Pakhlova, A. Paladino, T. Pang, A. Panta, E. Paoloni, S. Pardi, K. Parham, H. Park, S. -H. Park, B. Paschen, A. Passeri, A. Pathak, S. Patra, S. Paul, T. K. Pedlar, I. M. Peruzzi, R. Peschke, R. Pestotnik, F. Pham, M. Piccolo, L. E. Piilonen, G. Pinna Angioni, P. L. M. Podesta-Lerma, T. Podobnik, S. Pokharel, L. Polat, V. Popov, C. Praz, S. Prell, E. Prencipe, M. T. Prim, M. V. Purohit, H. Purwar, N. Rad, P. Rados, G. Raeuber, S. Raiz, A. Ramirez Morales, N. Rauls, M. Reif, S. Reiter, M. Remnev, I. Ripp-Baudot, M. Ritter, M. Ritzert, G. Rizzo, L. B. Rizzuto, S. H. Robertson, P. Rocchetti, D. Rodríguez Pérez, M. Röhrken, J. M. Roney, C. Rosenfeld, A. Rostomyan, N. Rout, M. Różańska, G. Russo, D. Sahoo, Y. Sakai, D. A. Sanders, S. Sandilya, A. Sangal, L. Šantelj, P. Sartori, Y. Sato, V. Savinov, B. Scavino, C. Schmitt, J. Schmitz, M. Schnepf, H. Schreeck, J. Schueler, C. Schwanda, A. J. Schwartz, B. Schwenker, M. Schwickardi, Y. Seino, A. Selce, K. Senyo, J. Serrano, M. E. Sevior, C. Sfienti, C. Sharma, V. Shebalin, Chun Shen, X. Shi, H. Shibuya, T. Shillington, J.-G. Shiu, D. Shtol, B. Shwartz, A. Sibidanov, F. Simon, J. B. Singh, J. Skorupa, K. Smith, R. Sobie, A. Soffer, Y. Soloviev, E. Solovieva, S. Spataro, B. Spruck, M. Starič, P. Stavroulakis, S. Stefkova, Z. S. Stottler, R. Stroili, J. Strube, J. Stypula, Y. Sue, R. Sugiura, M. Sumihama, K. Sumisawa, W. Sutcliffe, S. Suzuki, H. Svidras, M. Tabata, M. Takahashi, M. Takizawa, U. Tamponi, S. Tanaka, K. Tanida, H. Tanigawa, N. Taniguchi, Y. Tao, F. Tenchini, A. Thaller, O. Tittel, R. Tiwary, D. Tonelli, E. Torassa, N. Toutounji, K. Trabelsi, I. Tsaklidis, T. Tsuboyama, N. Tsuzuki, M. Uchida, I. Ueda, S. Uehara, Y. Uematsu, T. Ueno, T. Uglov, K. Unger, Y. Unno, K. Uno, S. Uno, P. Urquijo, Y. Ushiroda, Y. Usov, S. Vahsen, R. van Tonder, G. Varner, K. E. Varvell, A. Vinokurova, V. S. Vismaya, L. Vitale, V. Vobbilisetti, V. Vorobyev, A. Vossen, B. Wach, E. Waheed, M. Wakai, H. M. Wakeling, S. Wallner, W. Wan Abdullah, B. Wang, C. H. Wang, E. Wang, M.-Z. Wang, X. L. Wang, Z. Wang, A. Warburton, M. Watanabe, S. Watanuki, J. Angus Webb, S. Wehle, M. Welsch, O. Werbycka, C. Wessel, J. Wiechczynski, P. Wieduwilt, H. Windel, E. Won, L. J. Wu, Y. Xie, X. P. Xu, B. Yabsley, S. Yamada, W. B. Yan, S. B. Yang, J. Yelton, J. H. Yin, Y. Yook, K. Yoshihara, C. Z. Yuan, Y. Yusa, L. Zani, J. Z. Zhang, Y. Zhang, Z. Zhang, V. Zhilich, J. S. Zhou, Q. Zhou, Xiaokang Zhou, V. Zhukova, V. Zhulanov, R. Žlebčík
Bibliographic record
VenuearXiv (Cornell University) · 2023
Typepreprint
Languageen
FieldPhysics and Astronomy
TopicParticle physics theoretical and experimental studies
Canadian institutionsnot available
FundersInstitut National de Physique Nucléaire et de Physique des ParticulesJapan Society for the Promotion of ScienceNatural Sciences and Engineering Research Council of CanadaKorea Research Environment Open NetworkCentro 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 EconomicsAkademi Sains MalaysiaMinistry of Science and Technology, IsraelTürkiye Bilimsel ve Teknolojik Araştırma KurumuMax-Planck-GesellschaftMinistry of Education, Culture, Sports, Science and TechnologyKorea Institute of Science and Technology InformationLiaoning Revitalization Talents ProgramBundesministerium für Bildung und ForschungKorea Institute of Science and TechnologyDeutsches Elektronen-SynchrotronThailand Center of Excellence in PhysicsGeneralitat ValencianaNational Research FoundationAustrian Science FundCAS Center for Excellence in Particle PhysicsChinese Academy of SciencesU.S. Department of EnergyNational Natural Science Foundation of ChinaDeutsche ForschungsgemeinschaftJavna Agencija za Raziskovalno Dejavnost RSNational Institute of InformaticsGrantová 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 FoundationCanarieCentre National de la Recherche ScientifiqueUniverzita Karlova v Praze
KeywordsPhysicsParticle physicsLeptonColliderLuminosityBranching fractionNuclear physicsPhysics beyond the Standard ModelMesonElectronAstrophysics
Abstract
We report a search for lepton-flavor-violating decays $τ^- \to \ell^- ϕ$ ($\ell^- =e^-,μ^-$) at the Belle II experiment, using a sample of electron-positron data produced at the SuperKEKB collider in 2019-2021 and corresponding to an integrated luminosity of 190 fb$^{-1}$. We use a new untagged selection for $e^+e^- \to τ^+τ^-$ events, where the signal $τ$ is searched for as a neutrinoless final state of a single charged lepton and a $ϕ$ meson and the other $τ$ is not reconstructed in any specific decay mode, in contrast to previous measurements by the BaBar and Belle experiments. We find no evidence for $τ^- \to \ell^- ϕ$ decays and obtain upper limits on the branching fractions at 90% confidence level of 23 $\times 10^{-8}$ and 9.7$\times 10^{-8}$ for $τ^- \rightarrow e^-ϕ$ and $τ^- \rightarrow μ^-ϕ$, respectively
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)0.002
metaresearch head score (Gemma)0.002
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: Observational
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.014
Threshold uncertainty score0.028
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.002 |
| 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) | 0.004 | 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 head0.153
GPT teacher head0.267
Teacher spread0.114 · 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 designObservational
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
Published2023
Admission routes1
Has abstractyes