SU(3) predictions for charmed-baryon decays

Search for CP violation and measurement of branching fractions and decay asymmetry parameters for Λc+→Λh+ and Λc+→Σ0h+ (h=K,π)

We report a study of Λ_c⁺→Λh⁺ and Λ_c⁺→Σ⁰h⁺ (h=K,π) decays based on a data sample of 980fb^-1 collected with the Belle detector at the KEKB energy-asymmetric e⁺e^- collider. The first results of direct CP asymmetry in two-body singly Cabibbo-suppressed (SCS) decays of charmed baryons are measured, A_CP^dir(Λ_c⁺→ΛK⁺)=+0.021±0.026±0.001 and A_CP^dir(Λ_c⁺→Σ⁰K⁺)=+0.025±0.054±0.004. We also make the most precise measurement of the decay asymmetry parameters (α) for the four modes of interest and search for CP violation via the α-induced CP asymmetry (A_CP^α). We measure A_CP^α(Λ_c⁺→ΛK⁺)=-0.023±0.086±0.071 and A_CP^α(Λ_c⁺→Σ⁰K⁺)=+0.08±0.35±0.14, which are the first A_CP^α results for SCS decays of charmed baryons. We search for Λ-hyperon CP violation in Λ_c⁺→(Λ,Σ⁰)π⁺ and find A_CP^α(Λ→pπ^-)=+0.013±0.007±0.011. This is the first time that hyperon CP violation has been measured via Cabibbo-favored charm decays. No evidence of baryon CP violation is found. We also obtain the most precise branching fractions for two SCS Λ_c⁺ decays, B(Λ_c⁺→ΛK⁺)=(6.57±0.17±0.11±0.35)×10^-4 and B(Λ_c⁺→Σ⁰K⁺)=(3.58±0.19±0.06±0.19)×10^-4. The first uncertainties are statistical and the second systematic, while the third uncertainties come from the uncertainties on the world average branching fractions of Λ_c⁺→(Λ,Σ⁰)π⁺.

Recent Measurements of Decay Asymmetry Parameter and CP Asymmetry for Charmed Baryon Decays at Belle

We review the recent results from the Belle experiment on the measurements of branching fractions and decay asymmetry parameters (α) for the hadronic weak decays of charmed baryons, including Λc+→B+P: Λc+→(Λ,Σ0)h+ (h=π,K) and Λc+→Σ+(π0,η,η′); Ξc0→B+P: Ξc0→Ξ−π+; Ξc0→B+V: Ξc0→ΛK¯*0, Ξc0→Σ0K¯*0, and Ξc0→Σ+K*−. In addition, we present an overview of the searches for CP violation via the α-induced CP asymmetry for Λc+→(Λ,Σ0)h+ and Ξc0→Ξ−π+. Finally, we discuss the promising decay modes of Ωc0 which can be measured in the near future and are indispensable in searching for CP violation in the charm sector.