Search for Bs0 → l∓τ± with the semi-leptonic tagging method at Belle

Nayak, L.Nishida, S.Giri, A.Adachi, I.Aihara, H.Asner, D. M.Atmacan, H.Aulchenko, V.Aushev, T.Ayad, R.Babu, V.Bahinipati, S.Banerjee, S.Bauer, M.Behera, P.Belous, K.Bennett, J.Bessner, M.Bhuyan, B.Biswas, D.Bodrov, D.Borah, J.Bozek, A.Bracko, M.Branchini, P.Browder, T. E.Budano, A.Campajola, M.Cervenkov, D.Chang, M. -C.Cheon, B. G.Chilikin, K.Cho, H. E.Cho, K.Choi, S. -K.Choi, Y.Choudhury, S.Cinabro, D.Cochran, J.Das, S.Dash, N.De Nardo, G.De Pietro, G.Dhamija, R.Di Capua, F.Dingfelder, J.Dolezal, Z.Dong, T. V.Dossett, D.Dubey, S.Epifanov, D.Ferber, T.Ferlewicz, D.Fulsom, B. G.Garg, R.Gaur, V.Goldenzweig, P.Graziani, E.Gu, T.Guan, Y.Halder, S.Hara, T.Hayasaka, K.Hayashii, H.Hedges, M. T.Herrmann, D.Hou, W. -S.Hsu, C. -L.Iijima, T.Inami, K.Inguglia, G.Ipsita, N.Ishikawa, A.Itoh, R.Iwasaki, M.Jacobs, W. W.Jang, E. -J.Jia, S.Jin, Y.Joo, K. K.Kaliyar, A. B.Kawasaki, T.Kiesling, C.Kim, C. H.Kim, D. Y.Kim, K. -H.Kim, Y. -K.Kinoshita, K.Kodys, P.Konno, T.Korobov, A.Korpar, S.Kovalenko, E.Krizan, P.Krokovny, P.Kuhr, T.Kumar, M.Kumar, R.Kumara, K.Kuzmin, A.Kwon, Y. -J.Lee, S. C.Li, J.Li, L. K.Li, Y.Libby, J.Lieret, K.Lin, Y. -R.Liventsev, D.Luo, T.Ma, Y.Masuda, M.Matsuda, T.Maurya, S. K.Meier, F.Merola, M.Metzner, F.Miyabayashi, K.Mizuk, R.Mohanty, G. B.Nakamura, I.Nakao, M.Natkaniec, Z.Natochii, A.Nisar, N. K.Ogawa, S.Ono, H.Oskin, P.Pakhlov, P.Pakhlova, G.Pang, T.Pardi, S.Park, J.Park, S. -H.Passeri, A.Paul, S.Pedlar, T. K.Pestotnik, R.Piilonen, Leo E.Podobnik, T.Prencipe, E.Prim, M. T.Rostomyan, A.Rout, N.Russo, G.Sandilya, S.Sangal, A.Santelj, L.Savinov, V.Schnell, G.Schwanda, C.Schwartz, A. J.Seino, Y.Senyo, K.Sevior, M. E.Shapkin, M.Sharma, C.Shiu, J. -G.Sibidanov, A.Solovieva, E.Staric, M.Sumihama, M.Sumiyoshi, T.Takizawa, M.Tanida, K.Tenchini, F.Trabelsi, K.Uchida, M.Unno, Y.Uno, K.Uno, S.Urquijo, P.Vahsen, S. E.Varner, G.Varvell, K. E.Vinokurova, A.Wang, D.Wang, M. -Z.Watanuki, S.Won, E.Yabsley, B. D.Yan, W.Yelton, J.Yook, Y.Yuan, C. Z.Yuan, L.Yusa, Y.Zhai, Y.Zhang, Z. P.Zhilich, V.Zhukova, V.2023-12-082023-12-082023-08-282023-08-281029-8479https://hdl.handle.net/10919/117145Abstract We present a search for the lepton-flavor-violating decays $$ {B}_s^0 $$<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>B</mml:mi> <mml:mi>s</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> </mml:math> → ℓ∓τ±, where ℓ = e, μ, using the full data sample of 121 fb−1 collected at the Υ(5S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. We use $$ {B}_s^0{\overline{B}}_s^0 $$<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>B</mml:mi> <mml:mi>s</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> <mml:msubsup> <mml:mover> <mml:mi>B</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mi>s</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> </mml:math> events in which one $$ {B}_s^0 $$<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>B</mml:mi> <mml:mi>s</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> </mml:math> meson is reconstructed in a semileptonic decay mode and the other in the signal mode. We find no evidence for $$ {B}_s^0 $$<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>B</mml:mi> <mml:mi>s</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> </mml:math>→ ℓ∓τ± decays and set upper limits on their branching fractions at 90% confidence level as $$ \mathcal{B} $$<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>B</mml:mi> </mml:math>($$ {B}_s^0 $$<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>B</mml:mi> <mml:mi>s</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> </mml:math>→ e∓τ±) < 14 × 10−4 and $$ \mathcal{B} $$<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>B</mml:mi> </mml:math>($$ {B}_s^0 $$<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>B</mml:mi> <mml:mi>s</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> </mml:math>→ μ∓τ±) < 7.3 × 10−4. Our result represents the first upper limit on the $$ {B}_s^0 $$<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>B</mml:mi> <mml:mi>s</mml:mi> <mml:mn>0</mml:mn> </mml:msubsup> </mml:math>→ e∓τ± decay rate.13 page(s)enIn CopyrightScience & TechnologyPhysical SciencesPhysics, Particles & FieldsPhysicsB Physicse(+)-e(-) ExperimentsFlavour PhysicsIDENTIFICATION5106 Nuclear and Plasma Physics5107 Particle and High Energy Physics4902 Mathematical Physics49 Mathematical Sciences51 Physical SciencesSearch for Bs0 → l∓τ± with the semi-leptonic tagging method at BelleArticleJournal of High Energy Physicshttps://doi.org/10.1007/JHEP08(2023)17820238Piilonen, Leo [0000-0001-6836-0748]1029-8479