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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 | 2023/05 |
| 形態種別 | その他 |
| 標題 | Search for lepton-flavor-violating $τ^- \to \ell^-φ$ decays in 2019-2021 Belle II data |
| 執筆形態 | その他 |
| 著者・共著者 | Belle II Collaboration,F. Abudinén,I. Adachi,K. Adamczyk,L. Aggarwal,P. Ahlburg,H. Ahmed,J. K. Ahn,H. Aihara,N. Akopov,A. Aloisio,L. Andricek,N. Anh Ky,D. M. Asner,H. Atmacan,V. Aulchenko,T. Aushev,V. Aushev,M. Aversano,V. Babu,S. Bacher,H. Bae,S. Bahinipati,A. M. Bakich,P. Bambade,Sw. Banerjee,S. Bansal,M. Barrett,G. Batignani,J. Baudot,M. Bauer,A. Baur,A. Beaulieu,J. Becker,P. K. Behera,J. V. Bennett,E. Bernieri,F. U. Bernlochner,V. Bertacchi,M. Bertemes,E. Bertholet,M. Bessner,S. Bettarini,V. |
| 概要 | We report a search for lepton-flavor-violating decays $\tau^- \to \ell^-
\phi$ ($\ell^- =e^-,\mu^-$) at the Belle II experiment, using a sample of electron-positron data produced at the SuperKEKB collider in 2019-2021 and corresponding to an integrated luminosity of 190 fb$^{-1}$. We use a new untagged selection for $e^+e^- \to \tau^+\tau^-$ events, where the signal $\tau$ is searched for as a neutrinoless final state of a single charged lepton and a $\phi$ meson and the other $\tau$ is not reconstructed in any specific decay mode, in contrast to previous measurements by the BaBar and Belle experiments. We find no evidence for $\tau^- \to \ell^- \phi$ decays and obtain upper limits on the branching fractions at 90% confidence level of 23 $\times 10^{-8}$ and 9.7$\times 10^{-8}$ for $\tau^- \rightarrow e^-\phi$ and $\tau^- \rightarrow \mu^-\phi$, respectively |
| PermalinkURL | http://arxiv.org/abs/2305.04759v3 |
| researchmap用URL | http://arxiv.org/pdf/2305.04759v3 |