Measurement of branching-fraction ratios and $CP$ asymmetries in $B^{\pm} \to D_{CP\pm} K^{\pm}$ decays at Belle and Belle II

Sumitted to PubDB: 2023-03-08

Category: Physics / performance paper

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Principal Authors Tao Luo, Karim Trabelsi, Yi Zhang
Date 2024-05-17
Working group B Hadronic
Belle II Number BELLE2-PUB-PH-2023-018
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 $0.321<r_{B}<0.465$.
ArXiv https://arxiv.org/abs/2308.05048
Inspire https://inspirehep.net/literature/2686639
DOI 10.1007/JHEP05(2024)212
Reference JHEP 05, 212 (2024)
Bibtex 
@article{Belle:2023yoe,
    author = "Adachi, I. and others",
    collaboration = "Belle, Belle-II",
    title = "{Measurement of branching-fraction ratios and CP asymmetries in B$^{±}$ {\textrightarrow} D$_{CP±}$K$^{±}$ decays at Belle and Belle II}",
    eprint = "2308.05048",
    archivePrefix = "arXiv",
    primaryClass = "hep-ex",
    reportNumber = "Belle II Preprint 2023-011;KEK Preprint 2023-9",
    doi = "10.1007/JHEP05(2024)212",
    journal = "JHEP",
    volume = "05",
    pages = "212",
    year = "2024"
}
Journal JHEP

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