We report results from a study of B^\pm \rightarrow DK^\pm decays followed by D decaying to CP~eigenstates, where D indicates a D^0 or \bar{D}^{0} meson. These decays are sensitive to the Cabibbo-Kobayashi-Maskawa unitarity-triangle angle \phi_{3}. The results are based on a combined analysis of the final data set of 772 \times 10^6~B\bar{B} pairs collected by the Belle experiment and a data set of 198 \times 10^6~B\bar{B} pairs collected by the Belle~II experiment, both in electron-positron collisions at the \Upsilon(4S) resonance. We measure the CP asymmetries to be \mathcal{ A}_{CP +} =~(+12.5 \pm 5.8 \pm 1.4)\% and \mathcal{ A}_{CP -} =~(-16.7 \pm 5.7 \pm 0.6)\%, and the ratios of branching fractions to be \mathcal{ R}_{CP+}=~1.164 \pm 0.081 \pm 0.036 and \mathcal{ R}_{CP-} =~1.151 \pm 0.074 \pm 0.019. The first contribution to the uncertainties is statistical, and the second is systematic. The asymmetries \mathcal{A}_{CP +} and \mathcal{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^{\circ}<\phi_{3}<16.5^{\circ}) or (84.5^{\circ}<\phi_{3}<95.5^{\circ}) or (163.3^{\circ}<\phi_{3}<171.5^{\circ}) and 0.321<0.465.

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

Tenchini, F.;
2024-01-01

Abstract

We report results from a study of B^\pm \rightarrow DK^\pm decays followed by D decaying to CP~eigenstates, where D indicates a D^0 or \bar{D}^{0} meson. These decays are sensitive to the Cabibbo-Kobayashi-Maskawa unitarity-triangle angle \phi_{3}. The results are based on a combined analysis of the final data set of 772 \times 10^6~B\bar{B} pairs collected by the Belle experiment and a data set of 198 \times 10^6~B\bar{B} pairs collected by the Belle~II experiment, both in electron-positron collisions at the \Upsilon(4S) resonance. We measure the CP asymmetries to be \mathcal{ A}_{CP +} =~(+12.5 \pm 5.8 \pm 1.4)\% and \mathcal{ A}_{CP -} =~(-16.7 \pm 5.7 \pm 0.6)\%, and the ratios of branching fractions to be \mathcal{ R}_{CP+}=~1.164 \pm 0.081 \pm 0.036 and \mathcal{ R}_{CP-} =~1.151 \pm 0.074 \pm 0.019. The first contribution to the uncertainties is statistical, and the second is systematic. The asymmetries \mathcal{A}_{CP +} and \mathcal{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^{\circ}<\phi_{3}<16.5^{\circ}) or (84.5^{\circ}<\phi_{3}<95.5^{\circ}) or (163.3^{\circ}<\phi_{3}<171.5^{\circ}) and 0.321<0.465.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11586/580878
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