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  • Letter
  • Open Access

Large CP violation in Λb→ΛD decays and extraction of the Cabibbo-Kobayashi-Maskawa angle γ

Zhou Rui1,*, Zhi-Tian Zou1,†, Ya Li2,‡, and Ying Li1,§

  • *Contact author: jindui1127@126.com
  • †Contact author: zouzt@ytu.edu.cn
  • ‡Contact author: liyakelly@163.com
  • §Contact author: liying@ytu.edu.cn
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Phys. Rev. D 114, L031301 – Published 13 August, 2026

DOI: https://doi.org/10.1103/5bzh-p8cm

Abstract

Motivated by the first observation of CP violation in b-baryon decays, the search for baryonic decays exhibiting large CP violation will be a primary focus in the coming years. We propose that significant CP-violating effects exist in the decay Λb→ΛD, where D denotes a CP eigenstate of the D0−D¯0 system. The predicted CP asymmetries for both the CP-even and CP-odd modes can reach magnitudes as large as 50%, making these decays promising targets for measurement at the LHCb experiment. Additionally, we predict for the first time several nonzero CP-violating observables associated with angular distribution parameters, providing valuable complementary information in the search for CP violation in baryon decays. Furthermore, we propose a novel strategy to extract the Cabibbo-Kobayashi-Maskawa angle γ by combining data on angular distribution parameters and decay rates from the relevant channels. We emphasize that Λb→ΛD decays are among the most promising candidates for determining γ in the baryon sector. Our findings may offer new insights for future theoretical and experimental investigations.

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Phys. Rev. D 114, L031301– Published 13 August, 2026
  • Received 7 May 2026
  • Accepted 6 July 2026
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