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 KS0π0, where D is an admixture of D0 and D¯0 states. These decays are sensitive to the Cabibbo-Kobayashi-Maskawa unitarity-triangle angle ϕ3. The results are based on a combined analysis of the final data set of 772 × 106BB¯ pairs collected by the Belle experiment and a data set of 198 × 106BB¯ pairs collected by the Belle II experiment, both in electron-positron collisions at the Υ(4S) resonance. We measure the CP asymmetries to be ACP+ = (+12.5 ± 5.8 ± 1.4)% and ACP− = (−16.7 ± 5.7 ± 0.6)%, and the ratios of branching fractions to be RCP+ = 1.164 ± 0.081 ± 0.036 and RCP− = 1.151 ± 0.074 ± 0.019. The first contribution to the uncertainties is statistical, and the second is systematic. The asymmetries ACP+ and ACP− 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° < ϕ3 < 16.5°) or (84.5° < ϕ3 < 95.5°) or (163.3° < ϕ3 < 171.5°) and 0.321 < rB < 0.465.

Measurement of branching-fraction ratios and CP asymmetries in B± → DCP±K± decays at Belle and Belle II

Gabrielli, A.;Ganiev, E.;Ghosh, D.;Lanceri, L.;Manfredi, R.;Mantovano, M.;Raiz, S.;Vitale, L.;
2024-01-01

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 KS0π0, where D is an admixture of D0 and D¯0 states. These decays are sensitive to the Cabibbo-Kobayashi-Maskawa unitarity-triangle angle ϕ3. The results are based on a combined analysis of the final data set of 772 × 106BB¯ pairs collected by the Belle experiment and a data set of 198 × 106BB¯ pairs collected by the Belle II experiment, both in electron-positron collisions at the Υ(4S) resonance. We measure the CP asymmetries to be ACP+ = (+12.5 ± 5.8 ± 1.4)% and ACP− = (−16.7 ± 5.7 ± 0.6)%, and the ratios of branching fractions to be RCP+ = 1.164 ± 0.081 ± 0.036 and RCP− = 1.151 ± 0.074 ± 0.019. The first contribution to the uncertainties is statistical, and the second is systematic. The asymmetries ACP+ and ACP− 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° < ϕ3 < 16.5°) or (84.5° < ϕ3 < 95.5°) or (163.3° < ϕ3 < 171.5°) and 0.321 < rB < 0.465.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/3097939
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