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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 | 2021/03 |
| 形態種別 | その他 |
| 標題 | Measurements of the branching fractions of the semileptonic decays $Ξ_{c}^{0} \to Ξ^{-} \ell^{+} ν_{\ell}$ and the asymmetry parameter of $Ξ_{c}^{0} \to Ξ^{-} π^{+}$ |
| 執筆形態 | その他 |
| 著者・共著者 | Belle Collaboration,Y. B. Li,C. P. Shen,I. Adachi,K. Adamczyk,H. Aihara,S. Al Said,D. M. Asner,T. Aushev,R. Ayad,V. Babu,P. Behera,J. Bennett,M. Bessner,V. Bhardwaj,B. Bhuyan,T. Bilka,J. Biswal,G. Bonvicini,A. Bozek,M. Bračko,T. E. Browder,M. Campajola,D. Červenkov,M. -C. Chang,A. Chen,B. G. Cheon,K. Chilikin,K. Cho,S. -J. Cho,S. -K. Choi,Y. Choi,S. Choudhury,D. Cinabro,S. Cunliffe,S. Das,N. Dash,G. De Nardo,R. Dhamija,F. Di Capua,T. V. Dong,S. Eidelman,D. Epifanov,T. Ferber,B. G. Fulsom,R. Garg |
| 概要 | Using data samples of 89.5 and 711 fb$^{-1}$ recorded at energies of
$\sqrt{s}=10.52$ and $10.58$ GeV, respectively, with the Belle detector at the KEKB $e^+e^-$ collider, we report measurements of branching fractions of semileptonic decays $\Xi_{c}^{0} \to \Xi^{-} \ell^{+} \nu_{\ell}$ ($\ell=e$ or $\mu$) and the $CP$-asymmetry parameter of $\Xi_{c}^{0} \to \Xi^{-} \pi^{+}$ decay. The branching fractions are measured to be ${\cal B}(\Xi_{c}^{0} \to \Xi^{-} e^{+} \nu_{e})=(1.31 \pm 0.04 \pm 0.07 \pm 0.38)\%$ and ${\cal B}(\Xi_{c}^{0} \to \Xi^{-} \mu^{+} \nu_{\mu})=(1.27 \pm 0.06 \pm 0.10 \pm 0.37)\%$, and the decay parameter $\alpha_{\Xi\pi}$ is measured to be $0.63 \pm 0.03 \pm 0.01$ with much improved precision compared to the current world average. The corresponding ratio ${\cal B}(\Xi_{c}^{0} \to \Xi^{-} e^{+} \nu_{e})/{\cal B}(\Xi_{c}^{0} \to \Xi^{-} \mu^{+} \nu_{\mu})$ is $1.03 \pm 0.05\pm 0.07$, which is consistent with the expectation of lepton flavor universality. The first measured asymmetry parameter ${\cal A}_{CP} = (\alpha_{\Xi^{-}\pi^{+ } } + \alpha_{\bar{\Xi}^{+}\pi^{- } })/(\alpha_{\Xi^{-}\pi^{+ } } - \alpha_{\bar{\Xi}^{+}\pi^{- } }) = 0.024 \pm 0.052 \pm 0.014$ is found to be consistent with zero. The first and the second uncertainties above are statistical and systematic, respectively, while the third ones arise due to the uncertainty of the $\Xi_{c}^{0} \to \Xi^{-} \pi^+$ branching fraction. |
| DOI | 10.1103/PhysRevLett.127.121803 |
| PermalinkURL | http://arxiv.org/abs/2103.06496v4 |
| researchmap用URL | http://arxiv.org/pdf/2103.06496v4 |