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Measurement of the branching fraction and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>C</mml:mi><mml:mi>P</mml:mi></mml:math>-violating asymmetry of the decay <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>B</mml:mi><mml:mn>0</mml:mn></mml:msup><mml:mo stretchy="false">→</mml:mo><mml:msup><mml:mi>π</mml:mi><mml:mn>0</mml:mn></mml:msup><mml:msup><mml:mi>π</mml:mi><mml:mn>0</mml:mn></mml:msup></mml:math> using 387 million <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi mathvariant="normal">ϒ</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mn>4</mml:mn><mml:mi>S</mml:mi><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:math> decays in Belle II data
I. Adachi, L. Aggarwal, H. Ahmed, H. Aihara, M. Alhakami, A. Aloisio, N. Althubiti, N. Anh Ky, D. M. Asner, H. Atmacan, V. Aushev, M. Aversano, R. Ayad, V. Babu, H. Bae, N. K. Baghel, S. Bahinipati, P. Bambade, S. Banerjee, S. Bansal, 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, V. Bhardwaj, B. Bhuyan, F. Bianchi, T. Bilka, D. Biswas, A. Bobrov, D. Bodrov, A. E. Bolz, 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, J. Cerasoli, M.-C. Chang, P. Chang, R. Cheaib, P. Cheema, B. G. Cheon, 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 Marino, G. De Nardo, G. De Pietro, R. de Sangro, M. Destefanis, S. Dey, R. Dhamija, A. Di Canto, F. Di Capua, J. Dingfelder, Z. Doležal, I. Domínguez Jiménez, T. V. Dong, X. Dong, M. Dorigo, D. Dossett, S. Dubey, K. Dugic, G. Dujany, P. Ecker, D. Epifanov, J. Eppelt, P. Feichtinger, T. Ferber, T. Fillinger, C. Finck, G. Finocchiaro, A. Fodor, F. Forti, A. Frey, B. G. Fulsom, A. Gabrielli, E. Ganiev, M. Garcia-Hernandez, R. Garg, G. Gaudino, V. Gaur, A. Gaz, A. Gellrich, G. Ghevondyan, D. Ghosh, G. Giakoustidis, R. Giordano, A. Giri, P. Gironella Gironell, A. Glazov, B. Gobbo, R. Godang, O. Gogota, P. Goldenzweig, W. Gradl, S. Granderath, E. Graziani, D. Greenwald, Z. Gruberová, Y. Guan, K. Gudkova, I. Haide, S. Halder, Y. Han, T. Hara, C. Harris, K. Hayasaka, H. Hayashii, S. Hazra, C. Hearty, M. T. Hedges, A. Heidelbach, I. Heredia-De La Cruz, M. Hernández Villanueva, T. Higuchi, M. Hoek, M. Hohmann, R. HOPPE, P. Horak, C.-L. Hsu, T. Humair, T. Iijima, K. Inami, N. Ipsita, A. Ishikawa, R. Itoh, M. Iwasaki, P. Jackson, D. Jacobi, W. W. Jacobs, E.-J. Jang, Q. P. Ji, S. Jia, Y. Jin, A. Johnson, K. K. Joo, H. Junkerkalefeld, D. Kalita, A. B. Kaliyar, J. Kandra, K. H. Kang, S. Kang, G. Karyan, T. Kawasaki, F. Keil, C. Ketter, C. Kiesling, C. H. Kim, D. Y. Kim, K.-H. Kim, J.-Y. Kim, Y. J. Kim, Y.-K. Kim, K. Kinoshita, P. Kodyš, T. Koga, S. Kohani, K. Kojima, A. Korobov, S. Korpar, E. Kovalenko, R. Kowalewski, P. Križan, P. Krokovny, T. Kuhr, Y. Kulii, D. Kumar, M. Kumar, R. Kumar, K. Kumara, T. Kunigo, A. Kuzmin, Y.-J. Kwon, S. Lacaprara, Y.-T. Lai, K. Lalwani, T. Lam, L. Lanceri, J. S. Lange, T. S. Lau, M. Laurenza, K. Lautenbach, R. Leboucher, F. Le Diberder, M. J. Lee, C. Lemettais, P. Leo, D. Levit, P. Lewis, C. Li, L. K. Li, Q. M. Li, W. Z. Li, Y. B. Li, Y. P. Liao, J. Libby, J. Lin, S. Lin, M. H. Liu, Q. Y. Liu, Y. Liu, Zhiqing Liu, D. Liventsev, S. Longo, T. Lueck, C. Lyu, Yue Ma, C. Madaan, M. Maggiora, S. P. Maharana, R. Maiti, S. Maity, G. Mancinelli, R. Manfredi, E. Manoni, M. Mantovano, D. Marcantonio, S. Marcello, C. Mariñas, C. Martellini, A. Martens, A. Martini, T. Martinov, L. Massaccesi, M. Masuda, T. Matsuda, D. Matvienko, S. K. Maurya, M. Maushart, J. A. McKenna, R. Mehta, F. Meier, D. Meleshko, M. Merola, C. Miller, M. Mirra, S. Mitra, K. Miyabayashi, H. Miyake, R. Mizuk, G. B. Mohanty, S. Mondal, S. Moneta, H.-G. Moser, R. Mussa, I. Nakamura, M. Nakao, Y. Nakazawa, M. Naruki, Z. Natkaniec, A. Natochii, M. Nayak, G. Nazaryan, M. Neu, C. Niebuhr, S. Nishida, S. Ogawa, H. Ono, Y. Onuki, F. Otani, P. Pakhlov, G. Pakhlova, E. Paoloni, S. Pardi, K. Parham, H. Park, J. Park, K. Park, S.-H. Park, B. Paschen, A. Passeri, S. Patra, T. K. Pedlar, I. M. Peruzzi, R. Peschke, R. Pestotnik, M. Piccolo, L. E. Piilonen, P. L. M. Podesta-Lerma, T. Podobnik, S. Pokharel, C. Praz, S. Prell, E. Prencipe, M. T. Prim, I. Prudiiev, H. Purwar, P. Rados, G. Raeuber, S. Raiz, V P Jagathy Raj, N. Rauls, K. Ravindran, M. Reif, S. Reiter, M. Remnev, L. Reuter, D. Ricalde Herrmann, I. Ripp-Baudot, G. Rizzo, M. Röhrken, J. M. Roney, A. Rostomyan, N. Rout, D. A. Sanders, S. Sandilya, L. Šantelj, Y. Sato, V. Savinov, B. Scavino, C. Schmitt, S. Schneider, M. Schnepf, C. Schwanda, A. J. Schwartz, Y. Seino, A. Selce, K. Senyo, J. Serrano, M. E. Sevior, C. Sfienti, W. Shan, C. Sharma, C. P. Shen, X. Shi, T. Shillington, T. Shimasaki, J.-G. Shiu, D. Shtol, A. Sibidanov, F. Simon, J. B. Singh, J. Skorupa, R. Sobie, M. Sobotzik, A. Soffer, A. Sokolov, E. Solovieva, S. Spataro, B. Spruck, M. Starič, P. Stavroulakis, R. Stroili, J. Strube, Y. Sue, M. Sumihama, K. Sumisawa, W. Sutcliffe, N. Suwonjandee, H. Svidras, M. Takahashi, M. Takizawa, U. Tamponi, K. Tanida, F. Tenchini, A. Thaller, O. Tittel, R. Tiwary, D. Tonelli, E. Torassa, K. Trabelsi, I. Tsaklidis, M. Uchida, I. Ueda, K. Unger, Y. Unno, K. Uno, S. Uno, P. Urquijo, J. U. Rehman, Y. Ushiroda, S. Vahsen, R. van Tonder, K. E. Varvell, M. Veronesi, V. S. Vismaya, L. Vitale, V. Vobbilisetti, R. Volpe, A. Vossen, M. Wakai, S. Wallner, E. Wang, M.-Z. Wang, Z. Wang, A. Warburton, M. Watanabe, S. Watanuki, C. Wessel, E. Won, X. P. Xu, B. Yabsley, S. Yamada, W. B. Yan, S. B. Yang, J. Yelton, J. H. Yin, K. Yoshihara, J. Yuan, L. Zani, F. Zeng, Boyang Zhang, V. Zhilich, J. S. Zhou, Q. Zhou, V. Zhukova
Bibliographic record
VenuePhysical review. D/Physical review. D. · 2025
Typearticle
Languagelv
FieldPhysics and Astronomy
TopicParticle physics theoretical and experimental studies
Canadian institutionsnot available
FundersHORIZON EUROPE European Research CouncilCentro de Investigación y de Estudios Avanzados del Instituto Politécnico NacionalAkademi Sains MalaysiaJapan Society for the Promotion of ScienceDeutsches Elektronen-SynchrotronAustralian Research CouncilSeventh Framework ProgrammeKorea Research Environment Open NetworkNational Institute of InformaticsMinistry of Science and Higher Education of the Russian FederationHORIZON EUROPE Marie Sklodowska-Curie ActionsNational Research University Higher School of EconomicsGeneralitat ValencianaState Committee of ScienceMinistry of Science and Technology, IsraelBrookhaven National LaboratoryEuropean Research CouncilMax-Planck-GesellschaftCentre National de la Recherche ScientifiqueMinistry of Education and Science of UkraineNarodowe Centrum NaukiMinisterstwo Edukacji i NaukiNational Research FoundationJavna Agencija za Raziskovalno Dejavnost RSKnut och Alice Wallenbergs StiftelseNational Key Research and Development Program of ChinaIsrael Science FoundationKorea Institute of Science and TechnologyMinistry of Higher Education, MalaysiaNational Natural Science Foundation of ChinaNational Research Foundation of KoreaAgence Nationale de la RechercheKing Saud UniversityNatural Sciences and Engineering Research Council of CanadaMinistry of Education, Culture, Sports, Science and TechnologyBundesministerium für Bildung und ForschungAustrian Science FundGrantová Agentura České RepublikyAlexander von Humboldt-StiftungKorea Institute of Science and Technology InformationDepartment of Atomic Energy, Government of IndiaTürkiye Bilimsel ve Teknolojik Araştırma KurumuHigh Energy Accelerator Research OrganizationBundesministerium für Bildung, Wissenschaft und ForschungDeutsche ForschungsgemeinschaftNational Research Foundation of UkraineUniversiti MalayaMinistry of EducationDepartment of Science and Technology, Ministry of Science and Technology, IndiaInstitut National de Physique Nucléaire et de Physique des ParticulesUniversity of Petroleum and Energy StudiesInstituto Nazionale di Fisica NucleareUnited States-Israel Binational Science FoundationThailand Center of Excellence in PhysicsHelmholtz-GemeinschaftIstituto Nazionale di Fisica Nucleare Sezione di PadovaNatural Science Foundation of Shandong ProvinceCompute CanadaUniversity of TabukVietnam Academy of Science and TechnologyAgencia Estatal de InvestigaciónSecretaría de Educación PúblicaMinistry of Education and ScienceCanarieNational Science and Technology CouncilNational Science FoundationUniversity of VictoriaU.S. Department of Energy
KeywordsMathematicsArtificial intelligenceBranching (polymer chemistry)AlgorithmComputer scienceChemistry
Abstract
We measure the branching fraction and CP -violating flavor-dependent rate asymmetry of B0→π0π0 decays reconstructed using the Belle II detector in an electron-positron collision sample containing 387×106 ϒ(4S) mesons. Using an optimized event selection, we find 125±20 signal decays in a fit to background-discriminating and flavor-sensitive distributions. The resulting branching fraction is (1.25±0.23)×10−6 and the CP -violating asymmetry is 0.03±0.30 .
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 score0.024
Threshold uncertainty score0.079
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| 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) | 0.024 | 0.005 |
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 head0.021
GPT teacher head0.292
Teacher spread0.271 · 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
Citations1
Published2025
Admission routes1
Has abstractyes