English

Large CP violation in $\Lambda_b\rightarrow \Lambda D$ decays and extraction of the Cabibbo-Kobayashi-Maskawa angle $\gamma$

High Energy Physics - Phenomenology 2026-04-21 v1 High Energy Physics - Experiment

Abstract

Motivated by the first observation of CP violation in bb-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 ΛbΛD\Lambda_b \to \Lambda D, where DD denotes a CP eigenstate of the D0Dˉ0D^0 - \bar{D}^0 system. The predicted CP asymmetries for both the CP-even and CP-odd modes can reach magnitudes as large as 50%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 CKM angle γ\gamma by combining data on angular distribution parameters and decay rates from the relevant channels. We emphasize that ΛbΛD\Lambda_b \rightarrow \Lambda D decays are among the most promising candidates for determining γ\gamma in the baryon sector. Our findings may offer new insights for future theoretical and experimental investigations.

Keywords

Cite

@article{arxiv.2604.17877,
  title  = {Large CP violation in $\Lambda_b\rightarrow \Lambda D$ decays and extraction of the Cabibbo-Kobayashi-Maskawa angle $\gamma$},
  author = {Zhou Rui and Zhi-Tian Zou and Ya Li and Ying Li},
  journal= {arXiv preprint arXiv:2604.17877},
  year   = {2026}
}

Comments

7 pages, 1 figure, 7 tables