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Search for $C P$ violation in $Ξ_{c}^{+} \to Σ^{+} h^{+} h^{-}$ and $Λ_{c}^{+} \to p h^{+} h^{-}$ at Belle II

M. Abumusabh , I. Adachi , H. Ahmed , Y. Ahn , H. Aihara , N. Akopov , S. Alghamdi , M. Alhakami , N. Althubiti et al. (Belle II Collaboration)

N. Althubiti , K. Amos , N. Anh Ky , D. M. Asner , H. Atmacan , R. Ayad , V. Babu , N. K. Baghel , S. Bahinipati , P. Bambade , Sw. Banerjee , M. Bartl , J. Baudot , A. Beaubien , J. Becker , J. V. Bennett , V. Bertacchi , M. Bertemes , E. Bertholet , S. Bettarini , V. Bhardwaj , D. Biswas , A. Bobrov , D. Bodrov , G. Bonvicini , J. Borah , A. Boschetti , M. Bračko , P. Branchini , R. A. Briere , T. E. Browder , A. Budano , S. Bussino , Q. Campagna , M. Campajola , G. Casarosa , C. Cecchi , P. Chang , P. Cheema , L. Chen , B. G. Cheon , C. Cheshta , H. Chetri , K. Chilikin , J. Chin , K. Chirapatpimol , H.-E. Cho , K. Cho , S.-J. Cho , S.-K. Choi , S. Choudhury , S. Chutia , J. A. Colorado-Caicedo , I. Consigny , L. Corona , J. X. Cui , S. Das , S. A. De La Motte , G. De Nardo , G. De Pietro , R. de Sangro , M. Destefanis , A. Di Canto , Z. Doležal , I. Domínguez Jiménez , T. V. Dong , X. Dong , M. Dorigo , G. Dujany , P. Ecker , D. Epifanov , J. Eppelt , R. Farkas , P. Feichtinger , T. Ferber , T. Fillinger , G. Finocchiaro , F. Forti , B. G. Fulsom , A. Gabrielli , E. Ganiev , R. Garg , G. Gaudino , V. Gaur , V. Gautam , A. Gaz , A. Gellrich , D. Ghosh , H. Ghumaryan , R. Giordano , A. Giri , P. Gironella Gironell , A. Glazov , B. Gobbo , R. Godang , O. Gogota , P. Goldenzweig , W. Gradl , E. Graziani , D. Greenwald , K. Gudkova , I. Haide , Y. Han , S. Hazra , M. T. Hedges , A. Heidelbach , G. Heine , I. Heredia de la Cruz , M. Hernández Villanueva , D. Hettiarachchi , T. Higuchi , M. Hoek , M. Hohmann , R. Hoppe , P. Horak , X. T. Hou , C.-L. Hsu , T. Humair , T. Iijima , N. Ipsita , A. Ishikawa , R. Itoh , M. Iwasaki , W. W. Jacobs , D. E. Jaffe , E.-J. Jang , S. Jia , Y. Jin , A. Johnson , A. B. Kaliyar , J. Kandra , K. H. Kang , G. Karyan , F. Keil , C. Kiesling , D. Y. Kim , J.-Y. Kim , K.-H. Kim , K. Kinoshita , P. Kodyš , T. Koga , S. Kohani , A. Korobov , S. Korpar , E. Kovalenko , R. Kowalewski , P. Križan , P. Krokovny , T. Kuhr , K. Kumara , T. Kunigo , A. Kuzmin , Y.-J. Kwon , S. Lacaprara , T. Lam , T. S. Lau , M. Laurenza , R. Leboucher , F. R. Le Diberder , H. Lee , M. J. Lee , C. Lemettais , P. Leo , P. M. Lewis , C. Li , L. K. Li , Q. M. Li , W. Z. Li , Y. Li , Y. B. Li , Y. P. Liao , J. Libby , J. Lin , S. Lin , M. H. Liu , Q. Y. Liu , Z. Liu , D. Liventsev , S. Longo , T. Lueck , C. Lyu , J. L. Ma , Y. Ma , M. Maggiora , R. Manfredi , E. Manoni , M. Mantovano , D. Marcantonio , M. Marfoli , C. Marinas , C. Martellini , A. Martens , T. Martinov , L. Massaccesi , M. Masuda , D. Matvienko , S. K. Maurya , M. Maushart , J. A. McKenna , Z. Mediankin Gruberová , F. Meier , D. Meleshko , M. Merola , C. Miller , M. Mirra , K. Miyabayashi , R. Mizuk , G. B. Mohanty , S. Moneta , A. L. Moreira de Carvalho , H.-G. Moser , M. Mrvar , H. Murakami , I. Nakamura , M. Nakao , Y. Nakazawa , M. Naruki , Z. Natkaniec , A. Natochii , M. Nayak , M. Neu , S. Nishida , R. Nomaru , S. Ogawa , H. Ono , G. Pakhlova , A. Panta , S. Pardi , J. Park , S.-H. Park , A. Passeri , S. Patra , S. Paul , T. K. Pedlar , R. Pestotnik , L. E. Piilonen , P. L. M. Podesta-Lerma , T. Podobnik , C. Praz , S. Prell , E. Prencipe , M. T. Prim , H. Purwar , P. Rados , S. Raiz , K. Ravindran , J. U. Rehman , M. Reif , S. Reiter , 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 , C. Santos , B. Scavino , C. Schmitt , M. Schnepf , K. Schoenning , C. Schwanda , Y. Seino , K. Senyo , M. E. Sevior , C. Sfienti , W. Shan , G. Sharma , 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 , S. Spataro , B. Spruck , M. Starič , P. Stavroulakis , R. Stroili , M. Sumihama , M. Takahashi , U. Tamponi , S. S. Tang , K. Tanida , F. Tenchini , A. Thaller , T. Tien Manh , O. Tittel , R. Tiwary , E. Torassa , K. Trabelsi , F. F. Trantou , I. Ueda , K. Unger , Y. Unno , K. Uno , S. Uno , P. Urquijo , Y. Ushiroda , R. van Tonder , K. E. Varvell , M. Veronesi , V. S. Vismaya , L. Vitale , V. Vobbilisetti , R. Volpe , M. Wakai , S. Wallner , M.-Z. Wang , A. Warburton , S. Watanuki , C. Wessel , E. Won , X. P. Xu , B. D. Yabsley , W. Yan , K. Yi , J. H. Yin , K. Yoshihara , J. Yuan , Y. Yusa , L. Zani , F. Zeng , B. Zhang , V. Zhilich , J. S. Zhou , Q. D. Zhou , L. Zhu , and R. Žlebčík (Belle II Collaboration)

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Phys. Rev. D 113, 032017 – Published 24 February, 2026

DOI: https://doi.org/10.1103/s2gy-c3vh

Abstract

We report decay-rate $C P$ asymmetries of the singly-Cabibbo-suppressed decays $Ξ_{c}^{+} \to Σ^{+} h^{+} h^{-}$ and $Λ_{c}^{+} \to p h^{+} h^{-}$ , with $h = K$ , $π$ , measured using $428 {fb}^{- 1}$ of $e^{+} e^{-}$ collisions collected by the Belle II experiment at the SuperKEKB collider. The results, $A_{C P} (Ξ_{c}^{+} \to Σ^{+} K^{+} K^{-}) = (3.7 \pm 6.6 \pm 0.6) %$ , $A_{C P} (Ξ_{c}^{+} \to Σ^{+} π^{+} π^{-}) = (9.5 \pm 6.8 \pm 0.5) %$ , $A_{C P} (Λ_{c}^{+} \to p K^{+} K^{-}) = (3.9 \pm 1.7 \pm 0.7) %$ , $A_{C P} (Λ_{c}^{+} \to p π^{+} π^{-}) = (0.3 \pm 1.0 \pm 0.2) %$ , where the first uncertainties are statistical and the second systematic, agree with $C P$ symmetry. From these results we derive the sums $A_{C P} (Ξ_{c}^{+} \to Σ^{+} π^{+} π^{-}) + A_{C P} (Λ_{c}^{+} \to p K^{+} K^{-}) = (13.4 \pm 7.0 \pm 0.9) %$ , $A_{C P} (Ξ_{c}^{+} \to Σ^{+} K^{+} K^{-}) + A_{C P} (Λ_{c}^{+} \to p π^{+} π^{-}) = (4.0 \pm 6.6 \pm 0.7) %$ , which are consistent with the $U$ -spin symmetry prediction of zero. These are the first measurements of $C P$ asymmetries for individual hadronic three-body charmed-baryon decays.

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Phys. Rev. D 113, 032017– Published 24 February, 2026

Vol. 113, Iss. 3 — 1 February 2026

Received 1 October 2025
Accepted 22 January 2026

DOI: https://doi.org/10.1103/s2gy-c3vh

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.

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Search for $C P$ violation in $Ξ_{c}^{+} \to Σ^{+} h^{+} h^{-}$ and $Λ_{c}^{+} \to p h^{+} h^{-}$ at Belle II

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Search for CP violation in Ξc+→Σ+h+h− and Λc+→ph+h− at Belle II

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Search for $C P$ violation in $Ξ_{c}^{+} \to Σ^{+} h^{+} h^{-}$ and $Λ_{c}^{+} \to p h^{+} h^{-}$ at Belle II