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新山 雅之 所属 京都産業大学 理学部 物理科学科 職種 教授 |
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| 発行・発表の年月 | 2019/08 |
| 形態種別 | その他 |
| 査読 | 査読あり |
| 標題 | Test of lepton flavor universality in $B \to K \ell^{+}\ell^{-}$ decays |
| 執筆形態 | その他 |
| 著者・共著者 | A. Abdesselam,I. Adachi,K. Adamczyk,J. K. Ahn,H. Aihara,S. Al Said,K. Arinstein,Y. Arita,D. M. Asner,H. Atmacan,V. Aulchenko,T. Aushev,R. Ayad,T. Aziz,V. Babu,I. Badhrees,S. Bahinipati,A. M. Bakich,Y. Ban,V. Bansal,E. Barberio,M. Barrett,W. Bartel,P. Behera,C. Beleño,K. Belous,J. Bennett,M. Berger,F. Bernlochner,D. Besson,V. Bhardwaj,B. Bhuyan,T. Bilka,J. Biswal,T. Bloomfield,A. Bobrov,A. Bondar,G. Bonvicini,A. Bozek,M. Bračko,N. Braun,F. Breibeck,T. E. Browder,M. Campajola,L. Cao,G. Caria,D. Če |
| 概要 | We present measurements of the branching fractions for the decays $B\to K
\mu^{+}\mu^{-}$ and $B\to K e^{+}e^{-}$, and their ratio ($R_{K}$), using a data sample of 711 $fb^{-1}$ that contains $772 \times 10^{6}$ $B\bar{B}$ events. The data were collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. The ratio $R_{K}$ is measured in four bins of dilepton invariant-mass squared, $q^{2}$; the results are \begin{eqnarray*} R_{K} = \begin{cases} 0.95~ ^{+0.27}_{-0.24} \pm 0.06 & q^{2} \in (0.1,4.0)~\mathrm{\,GeV^2}c^4 \, , 0.81~ ^{+0.28}_{-0.23} \pm 0.05 & q^{2} \in (4.0,8.12)~\mathrm{\,GeV^2}c^4 \, , 0.98~ ^{+0.27}_{-0.23} \pm 0.06 & q^{2} \in (1.0,6.0)~\mathrm{\,GeV^2}c^4 \, , 1.11~ ^{+0.29}_{-0.26} \pm 0.07 & q^{2} > 14.18~\mathrm{\,GeV^2}c^4 \, . \end{cases} \end{eqnarray*} The first uncertainties listed are statistical, and the second uncertainties are systematic. The $R_{K}$ value in the whole $q^2$ range is found to be $1.06~ ^{+0.15}_{-0.14} \pm 0.07$. We also measure $CP-$averaged isospin asymmetries in the same $q^{2}$ bins; the results are consistent with a null asymmetry with the largest difference of 2.7 standard deviations is found in the $q^{2}\in(1.0,6.0)~\mathrm{\,GeV^2}c^4 \,$ bin in the mode with muon final states. The measured branching fractions are $\cal B\rm{\it(B\to K \mu^{+}\mu^{-})}= (5.5 \pm0.5 \pm0.3) \times 10^{-7}$ and $\cal B\rm{\it(B\to K e^{+}e^{-})} = (5.1 \pm 0.5 \pm0.3) \times 10^{-7}$. These results are compatible with standard model expectations. |
| DOI | 10.1007/JHEP03(2021)105 |
| PermalinkURL | http://arxiv.org/abs/1908.01848v3 |
| researchmap用URL | http://arxiv.org/pdf/1908.01848v3 |