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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 | 2018/07 |
| 形態種別 | その他 |
| 標題 | Measurements of isospin asymmetry and difference of direct $CP$ asymmetries in inclusive $B \to X_s γ$ decays |
| 執筆形態 | その他 |
| 著者・共著者 | S. Watanuki,A. Ishikawa,I. Adachi,H. Aihara,S. Al Said,D. M. Asner,T. Aushev,R. Ayad,V. Babu,I. Badhrees,A. M. Bakich,V. Bansal,P. Behera,C. Belen,M. Berger,V. Bhardwaj,B. Bhuyan,T. Bilka,J. Biswal,A. Bobrov,G. Bonvicini,A. Bozek,M. Brač,T. E. Browder,L. Cao,D. C,P. Chang,B. G. Cheon,K. Chilikin,K. Cho,Y. Choi,S. Choudhury,D. Cinabro,S. Cunliffe,S. Di Carlo,J. Dingfelder,T. V. Dong,S. Eidelman,D. Epifanov,J. E. Fast,T. Ferber,A. Frey,B. G. Fulsom,V. Gaur,N. Gabyshev,A. Garmash,M. Gelb,A. Giri,P. |
| 概要 | We report measurements of isospin asymmetry $\Delta_{0-}$ and difference of
direct $CP$ asymmetries $\Delta A_{CP}$ between charged and neutral $B \to X_s \gamma$ decays. This analysis is based on the data sample containing $772 \times 10^6 B\bar{B}$ pairs that was collected with the Belle detector at the KEKB energy-asymmetric $e^+ e^-$ collider. Using a sum-of-exclusive technique with invariant $X_s$ mass up to 2.8~GeV/$c^2$, we obtain $\Delta_{0-} = \bigl[-0.48 \pm 1.49 {\rm (stat.)} \pm 0.97 {\rm (syst.)} \pm 1.15 {(f_{+-}/f_{00})}\bigr]$\% and $\Delta A_{CP} = \bigl[+3.69 \pm 2.65 {\rm (stat.)} \pm 0.76{\rm (syst.)}\bigr]$\%, where the last uncertainty for $\Delta_{0-}$ is due to the uncertainty on the production ratio of $B^+B^-$ to $B^0\bar{B}^0$ in $\Upsilon(4S)$ decays. The measured value of $\Delta_{0-}$ is consistent with zero, allowing us to constrain the resolved photon contribution in the $B \to X_s \gamma$, and improve the branching fraction prediction. The result for $\Delta A_{CP}$ is consistent with the prediction of the SM. We also measure the direct $CP$ asymmetries for charged and neutral $B \to X_s \gamma$ decays. All the measurements are the most precise to date. |
| DOI | 10.1103/PhysRevD.99.032012 |
| PermalinkURL | http://arxiv.org/abs/1807.04236v4 |
| researchmap用URL | http://arxiv.org/pdf/1807.04236v4 |