Search for CP violation in Ξc^+Σ^+h^+h^- and Λc^+ ph^+h^- at Belle II

We report decay-rate CP asymmetries of the singly-Cabibbo-suppressed decays Ξc^+Σ^+h^+h^- and Λc^+ ph^+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, equation A₂₏ (Ξc^+Σ^+K^+K^-) = (3. 76. 60. 6) \%, equationequation A₂₏ (Ξc^+Σ^+π^+π^-) = (9. 56. 80. 5) \%, equationequation A₂₏ (Λc^+ pK^+K^-) = (3. 91. 70. 7) \%, equationequation A₂₏ (Λc^+ pπ^+π^-) = (0. 31. 00. 2) \%, equation where the first uncertainties are statistical and the second systematic, agree with CP symmetry. From these results we derive the sums equation A₂₏ (Ξc^+Σ^+π^+π^-) \, + \, A₂₏ (Λc^+ pK^+K^-) = (13. 4 7. 0 0. 9) \%, equationequation A₂₏ (Ξc^+Σ^+K^+K^-) \, + \, A₂₏ (Λc^+ pπ^+π^-) = (04. 0 6. 6 0. 7) \%, equation which are consistent with the U-spin symmetry prediction of zero. These are the first measurements of CP asymmetries for individual hadronic three-body charmed-baryon decays.