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Measurement of the time-integrated $C P$ asymmetry in $D^{0} \to K_{S}^{0} K_{S}^{0}$ decays using opposite-side flavor tagging at Belle and Belle II

I. Adachi , Y. Ahn , N. Akopov , S. Alghamdi , M. Alhakami , A. Aloisio , N. Althubiti , K. Amos , M. Angelsmark et al. (Belle and Belle II Collaborations)

M. Angelsmark , N. Anh Ky , C. Antonioli , D. M. Asner , H. Atmacan , T. Aushev , M. Aversano , R. Ayad , V. Babu , H. Bae , N. K. Baghel , S. Bahinipati , P. Bambade , Sw. Banerjee , M. Barrett , M. Bartl , J. Baudot , A. Baur , A. Beaubien , F. Becherer , J. Becker , J. V. Bennett , F. U. Bernlochner , V. Bertacchi , M. Bertemes , E. Bertholet , M. Bessner , S. Bettarini , B. Bhuyan , F. Bianchi , T. Bilka , D. Biswas , A. Bobrov , D. Bodrov , A. Bondar , J. Borah , A. Boschetti , A. Bozek , M. Bračko , P. Branchini , R. A. Briere , T. E. Browder , A. Budano , S. Bussino , M. Campajola , L. Cao , G. Casarosa , C. Cecchi , P. Cheema , B. G. Cheon , K. Chilikin , J. Chin , K. Chirapatpimol , H.-E. Cho , K. Cho , S.-J. Cho , S.-K. Choi , S. Choudhury , I. Consigny , L. Corona , J. X. Cui , E. De La Cruz-Burelo , S. A. De La Motte , G. de Marino , G. De Pietro , R. de Sangro , M. Destefanis , A. Di Canto , J. Dingfelder , Z. Doležal , I. Domínguez Jiménez , T. V. Dong , M. Dorigo , G. Dujany , P. Ecker , D. Epifanov , R. Farkas , P. Feichtinger , T. Ferber , T. Fillinger , C. Finck , G. Finocchiaro , A. Fodor , F. Forti , B. G. Fulsom , A. Gabrielli , A. Gale , E. Ganiev , M. Garcia-Hernandez , R. Garg , G. Gaudino , V. Gaur , V. Gautam , A. Gaz , A. Gellrich , 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 , Y. Han , H. Hayashii , S. Hazra , C. Hearty , M. T. Hedges , A. Heidelbach , G. Heine , I. Heredia de la Cruz , M. Hernández Villanueva , T. Higuchi , M. Hoek , M. Hohmann , P. Horak , C.-L. Hsu , T. Humair , T. Iijima , K. Inami , G. Inguglia , N. Ipsita , A. Ishikawa , R. Itoh , M. Iwasaki , P. Jackson , D. Jacobi , W. W. Jacobs , D. E. Jaffe , Q. P. Ji , S. Jia , Y. Jin , A. Johnson , J. Kandra , K. H. Kang , G. Karyan , T. Kawasaki , F. Keil , C. Ketter , M. Khan , C. Kiesling , D. Y. Kim , J.-Y. Kim , K.-H. Kim , K. Kinoshita , P. Kodyš , T. Koga , S. Kohani , K. Kojima , A. Korobov , S. Korpar , E. Kovalenko , R. Kowalewski , P. Križan , P. Krokovny , K. Kumara , T. Kunigo , A. Kuzmin , Y.-J. Kwon , K. Lalwani , T. Lam , J. S. Lange , T. S. Lau , M. Laurenza , R. Leboucher , F. R. Le Diberder , M. J. Lee , C. Lemettais , P. Leo , P. M. Lewis , H.-J. Li , L. K. Li , Q. M. Li , W. Z. Li , Y. Li , Y. B. Li , Y. P. Liao , J. Libby , J. Lin , S. Lin , V. Lisovskyi , M. H. Liu , Q. Y. Liu , Y. Liu , Z. Liu , D. Liventsev , S. Longo , C. Lyu , Y. Ma , C. Madaan , M. Maggiora , S. P. Maharana , 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 , S. K. Maurya , M. Maushart , J. A. McKenna , F. Meier , M. Merola , C. Miller , M. Mirra , S. Mitra , K. Miyabayashi , R. Mizuk , G. B. Mohanty , S. Moneta , H.-G. Moser , M. Nakao , H. Nakazawa , Y. Nakazawa , M. Naruki , Z. Natkaniec , A. Natochii , M. Nayak , M. Neu , S. Nishida , S. Ogawa , R. Okubo , H. Ono , E. R. Oxford , G. Pakhlova , S. Pardi , K. Parham , H. Park , J. Park , K. Park , S.-H. Park , A. Passeri , S. Patra , R. Pestotnik , L. E. Piilonen , P. L. M. Podesta-Lerma , T. Podobnik , A. Prakash , C. Praz , S. Prell , E. Prencipe , M. T. Prim , S. Privalov , H. Purwar , P. Rados , G. Raeuber , S. Raiz , V. Raj , K. Ravindran , J. U. Rehman , M. Reif , S. Reiter , M. Remnev , L. Reuter , D. Ricalde Herrmann , I. Ripp-Baudot , G. Rizzo , J. M. Roney , A. Rostomyan , N. Rout , L. Salutari , D. A. Sanders , S. Sandilya , L. Santelj , V. Savinov , B. Scavino , C. Schmitt , J. Schmitz , S. Schneider , G. Schnell , M. Schnepf , C. Schwanda , A. J. Schwartz , Y. Seino , A. Selce , K. Senyo , J. Serrano , M. E. Sevior , C. Sfienti , W. Shan , X. D. Shi , T. Shillington , J.-G. Shiu , D. Shtol , B. Shwartz , A. Sibidanov , F. Simon , J. Skorupa , R. J. Sobie , M. Sobotzik , A. Soffer , A. Sokolov , E. Solovieva , S. Spataro , B. Spruck , M. Starič , P. Stavroulakis , S. Stefkova , L. Stoetzer , R. Stroili , Y. Sue , M. Sumihama , N. Suwonjandee , H. Svidras , M. Takizawa , K. Tanida , F. Tenchini , F. Testa , O. Tittel , R. Tiwary , E. Torassa , K. Trabelsi , F. F. Trantou , I. Tsaklidis , M. Uchida , I. Ueda , T. Uglov , K. Unger , Y. Unno , K. Uno , S. Uno , Y. Ushiroda , R. van Tonder , K. E. Varvell , M. Veronesi , A. Vinokurova , V. S. Vismaya , L. Vitale , R. Volpe , A. Vossen , S. Wallner , M.-Z. Wang , A. Warburton , M. Watanabe , S. Watanuki , C. Wessel , E. Won , B. D. Yabsley , S. Yamada , W. Yan , S. B. Yang , J. Yelton , J. H. Yin , K. Yoshihara , J. Yuan , Y. Yusa , L. Zani , M. Zeyrek , B. Zhang , V. Zhilich , J. S. Zhou , Q. D. Zhou , L. Zhu , and R. Žlebčík (Belle and Belle II Collaborations)

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Phys. Rev. D 112, 012017 – Published 21 July, 2025

DOI: https://doi.org/10.1103/8x1h-39dp

Abstract

We measure the time-integrated $C P$ asymmetry in $D^{0} \to K_{S}^{0} K_{S}^{0}$ decays reconstructed in $e^{+} e^{-} \to c \bar{c}$ events collected by the Belle and Belle II experiments. The corresponding data samples have integrated luminosities of 980 and $428 {fb}^{- 1}$ , respectively. To infer the flavor of the $D^{0}$ meson, we exploit the correlation between the flavor of the reconstructed decay and the electric charges of particles reconstructed in the rest of the $e^{+} e^{-} \to c \bar{c}$ event. This results in a sample which is independent from any other previously used at Belle or Belle II. The result, $A_{C P} (D^{0} \to K_{S}^{0} K_{S}^{0}) = (1.3 \pm 2.0 \pm 0.2) %$ , where the first uncertainty is statistical and the second systematic, is consistent with previous determinations and with $C P$ symmetry.

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References (54)

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Phys. Rev. D 112, 012017– Published 21 July, 2025

Vol. 112, Iss. 1 — 1 July 2025

Received 23 April 2025
Accepted 10 June 2025

DOI: https://doi.org/10.1103/8x1h-39dp

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

Published by the American Physical Society

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Measurement of the time-integrated $C P$ asymmetry in $D^{0} \to K_{S}^{0} K_{S}^{0}$ decays using opposite-side flavor tagging at Belle and Belle II

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Measurement of the time-integrated CP asymmetry in D0→KS0KS0 decays using opposite-side flavor tagging at Belle and Belle II

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Measurement of the time-integrated $C P$ asymmetry in $D^{0} \to K_{S}^{0} K_{S}^{0}$ decays using opposite-side flavor tagging at Belle and Belle II