## Abstract

We report results from a study of B^{±}→ DK^{±} decays followed by D decaying to the CP-even final state K^{+}K^{−} and CP-odd final state K_{S}^{0}π^{0}, where D is an admixture of D^{0} and D¯^{0} states. These decays are sensitive to the Cabibbo-Kobayashi-Maskawa unitarity-triangle angle ϕ_{3}. The results are based on a combined analysis of the final data set of 772 × 10^{6}BB¯ pairs collected by the Belle experiment and a data set of 198 × 10^{6}BB¯ pairs collected by the Belle II experiment, both in electron-positron collisions at the Υ(4S) resonance. We measure the CP asymmetries to be A_{CP+} = (+12.5 ± 5.8 ± 1.4)% and A_{CP−} = (−16.7 ± 5.7 ± 0.6)%, and the ratios of branching fractions to be R_{CP+} = 1.164 ± 0.081 ± 0.036 and R_{CP−} = 1.151 ± 0.074 ± 0.019. The first contribution to the uncertainties is statistical, and the second is systematic. The asymmetries A_{CP+} and A_{CP−} have similar magnitudes and opposite signs; their difference corresponds to 3.5 standard deviations. From these values we calculate 68.3% confidence intervals of (8.5^{°} < ϕ_{3} < 16.5^{°}) or (84.5^{°} < ϕ_{3} < 95.5^{°}) or (163.3^{°} < ϕ_{3} < 171.5^{°}) and 0.321 < r_{B} < 0.465.

Original language | English |
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Article number | 212 |

Journal | Journal of High Energy Physics |

Volume | 2024 |

Issue number | 5 |

DOIs | |

State | Published - May 2024 |

## Keywords

- B Physics
- CKM Angle Gamma
- CP Violation
- e-e Experiments

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