Search for $B{}^0_s \rightarrow \ell^{\mp} τ^{\pm}$ with the Semi-leptonic Tagging Method at Belle
Creators: name: Belle Collaboration
name: Nayak, L.
name: Nishida, S.
name: Giri, A.
name: Adachi, I.
name: Aihara, H.
name: Asner, D. M.
name: Atmacan, H.
name: Aulchenko, V.
name: Aushev, T.
name: Ayad, R.
name: Babu, V.
name: Bahinipati, S.
name: Banerjee, Sw.
name: Bauer, M.
name: Behera, P.
name: Belous, K.
name: Bennett, J.
name: Bessner, M.
name: Bhuyan, B.
name: Biswas, D.
name: Bodrov, D.
name: Borah, J.
name: Bozek, A.
name: Bračko, M.
name: Branchini, P.
name: Browder, T. E.
name: Budano, A.
name: Campajola, M.
name: Červenkov, D.
name: Chang, M. -C.
name: Cheon, B. G.
name: Chilikin, K.
name: Cho, H. E.
name: Cho, K.
name: Choi, S. -K.
name: Choi, Y.
name: Choudhury, S.
name: Cinabro, D.
name: Cochran, J.
name: Das, S.
name: Dash, N.
name: De Nardo, G.
name: De Pietro, G.
name: Dhamija, R.
name: Di Capua, F.
name: Dingfelder, J.
name: Doležal, Z.
name: Dong, T. V.
name: Dossett, D.
name: Dubey, S.
name: Epifanov, D.
name: Ferber, T.
name: Ferlewicz, D.
name: Fulsom, B. G.
name: Garg, R.
name: Gaur, V.
name: Goldenzweig, P.
name: Graziani, E.
name: Gu, T.
name: Guan, Y.
name: Halder, S.
name: Hara, T.
name: Hayasaka, K.
name: Hayashii, H.
name: Hedges, M. T.
name: Herrmann, D.
name: Hou, W. -S.
name: Hsu, C. -L.
name: Iijima, T.
name: Inami, K.
name: Inguglia, G.
name: Ipsita, N.
name: Ishikawa, A.
name: Itoh, R.
name: Iwasaki, M.
name: Jacobs, W. W.
name: Jang, E. -J.
name: Jia, S.
name: Jin, Y.
name: Joo, K. K.
name: Kaliyar, A. B.
name: Kawasaki, T.
name: Kiesling, C.
name: Kim, C. H.
name: Kim, D. Y.
name: Kim, K. -H.
name: Kim, Y. -K.
name: Kinoshita, K.
name: Kodyš, P.
name: Konno, T.
name: Korobov, A.
name: Korpar, S.
name: Kovalenko, E.
name: Križan, P.
name: Krokovny, P.
name: Kuhr, T.
name: Kumar, M.
name: Kumar, R.
name: Kumara, K.
name: Kuzmin, A.
name: Kwon, Y. -J.
name: Lee, S. C.
name: Li, J.
name: Li, L. K.
name: Li, Y.
name: Libby, J.
name: Lieret, K.
name: Lin, Y. -R.
name: Liventsev, D.
name: Luo, T.
name: Ma, Y.
name: Masuda, M.
name: Matsuda, T.
name: Maurya, S. K.
name: Meier, F.
name: Merola, M.
name: Metzner, F.
name: Miyabayashi, K.
name: Mizuk, R.
name: Mohanty, G. B.
name: Nakamura, I.
name: Nakao, M.
name: Natkaniec, Z.
name: Natochii, A.
name: Nisar, N. K.
name: Ogawa, S.
name: Ono, H.
name: Oskin, P.
name: Pakhlov, P.
name: Pakhlova, G.
name: Pang, T.
name: Pardi, S.
name: Park, J.
name: Park, S. -H.
name: Passeri, A.
name: Paul, S.
name: Pedlar, T. K.
name: Pestotnik, R.
name: Piilonen, L. E.
name: Podobnik, T.
name: Prencipe, E.
name: Prim, M. T.
name: Rostomyan, A.
name: Rout, N.
name: Russo, G.
name: Sandilya, S.
name: Sangal, A.
name: Santelj, L.
name: Savinov, V.
name: Schnell, G.
name: Schwanda, C.
name: Schwartz, A. J.
name: Seino, Y.
name: Senyo, K.
name: Sevior, M. E.
name: Shapkin, M.
name: Sharma, C.
name: Shiu, J. -G.
name: Sibidanov, A.
name: Solovieva, E.
name: Starič, M.
name: Sumihama, M.
name: Sumiyoshi, T.
name: Takizawa, M.
name: Tanida, K.
name: Tenchini, F.
name: Trabelsi, K.
name: Uchida, M.
name: Unno, Y.
name: Uno, K.
name: Uno, S.
name: Urquijo, P.
name: Vahsen, S. E.
name: Varner, G.
name: Varvell, K. E.
name: Vinokurova, A.
name: Wang, D.
name: Wang, M. -Z.
name: Watanuki, S.
name: Won, E.
name: Yabsley, B. D.
name: Yan, W.
name: Yelton, J.
name: Yook, Y.
name: Yuan, C. Z.
name: Yuan, L.
name: Yusa, Y.
name: Zhai, Y.
name: Zhang, Z. P.
name: Zhilich, V.
name: Zhukova, V.
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We present a search for the lepton-flavor-violating decays $B{}^0_s \rightarrow \ell^{\mp}τ^{\pm}$, where $\ell = e, μ$, using the full data sample of $121~\mathrm{fb}^{-1}$ collected at the $Υ(5S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We use $B{}^0_s \overline{B}{}^0_s$ events in which one $B{}^0_s$ meson is reconstructed in a semileptonic decay mode and the other in the signal mode. We find no evidence for $B{}^0_s \rightarrow \ell^{\mp}τ^{\pm}$ decays and set upper limits on their branching fractions at $90\%$ confidence level as $\mathcal{B}(B{}^0_s \rightarrow e^{\mp}τ^{\pm}) &lt; 14 \times 10^{-4}$ and $\mathcal{B}(B{}^0_s \rightarrow μ^{\mp}τ^{\pm}) &lt; 7.3 \times 10^{-4}$. Our result represents the first upper limit on the $B{}^0_s \rightarrow e^{\mp}τ^{\pm}$ decay rate.
description: 14 pages, 5 figures