Li, Y. B.Shen, C. P.Adachi, I.Aihara, H.Al Said, S.Asner, D. M.Atmacan, H.Aushev, T.Ayad, R.Babu, V.Bahinipati, S.Behera, P.Belous, K.Bennett, J.Bernlochner, F.Bessner, M.Bhuyan, B.Bilka, T.Bobrov, A.Bodrov, D.Borah, J.Bozek, A.Bracko, M.Branchini, P.Browder, T. E.Budano, A.Campajola, M.Cervenkov, D.Chang, M. -C.Chang, P.Chekelian, V.Chen, A.Cheon, B. G.Chilikin, K.Cho, H. E.Cho, K.Cho, S. -J.Choi, S. -K.Choi, Y.Choudhury, S.Cinabro, D.Cunliffe, S.Dash, N.De Nardo, G.De Pietro, G.Dhamija, R.Di Capua, F.Dingfelder, J.Dolezal, Z.V. Dong, T.Ferber, T.Ferlewicz, D.Fulsom, B. G.Garg, R.Gaur, V.Gabyshev, N.Giri, A.Goldenzweig, P.Golob, B.Graziani, E.Gudkova, K.Hadjivasiliou, C.Hara, T.Hayasaka, K.Hayashii, H.Hedges, M. T.Hou, W. -S.Inami, K.Inguglia, G.Ishikawa, A.Itoh, R.Iwasaki, M.Iwasaki, Y.Jacobs, W. W.Jang, E. -J.Jia, S.Jin, Y.Joo, K. K.Kahn, J.Kang, K. H.Kawasaki, T.Kichimi, H.Kiesling, C.Kim, C. H.Kim, D. Y.Kim, K. -H.Kim, K. T.Kim, Y. -K.Kinoshita, K.Kodys, P.Konno, T.Korobov, A.Korpar, S.Kovalenko, E.Krizan, P.Kroeger, R.Krokovny, P.Kumar, M.Kumar, R.Kumara, K.Kuzmin, A.Kwon, Y. -J.Lalwani, K.Lam, T.Laurenza, M.Lee, S. C.Li, J.Li, L. K.Li, Y.Li Gioi, L.Libby, J.Lieret, K.Liventsev, D.Martini, A.Masuda, M.Matvienko, D.Maurya, S. K.Merola, M.Miyabayashi, K.Mizuk, R.Mohanty, G. B.Nakao, M.Narwal, D.Natochii, A.Nayak, L.Nayak, M.Nisar, N. K.Nishida, S.Ogawa, K.Ogawa, S.Ono, H.Oskin, P.Pakhlov, P.Pakhlova, G.Pang, T.Pardi, S.Park, S. -H.Patra, S.Paul, S.Pedlar, T. K.Pestotnik, R.Piilonen, L. E.Podobnik, T.Prencipe, E.Prim, M. T.Roehrken, M.Rostomyan, A.Rout, N.Russo, G.Sahoo, D.Sandilya, S.Sangal, A.Santelj, L.Savinov, V.Schnell, G.Schueler, J.Schwanda, C.Seino, Y.Senyo, K.Sevior, M. E.Shapkin, M.Sharma, C.Shebalin, V.Shiu, J. -G.Shwartz, B.Singh, J. B.Sokolov, A.Solovieva, E.Staric, M.Stottler, Z. S.Sumihama, M.Sumiyoshi, T.Takizawa, M.Tamponi, U.Tanida, K.Tenchini, F.Uchida, M.Uglov, T.Unno, Y.Uno, K.Uno, S.Urquijo, P.Vahsen, S. E.Van Tonder, R.Varner, G.Vinokurova, A.Waheed, E.Wang, D.Wang, E.Wang, M. -Z.Watanuki, S.Won, E.Xu, X.Yabsley, B. D.Yan, W.Yang, S. B.Ye, H.Yelton, J.Yin, J. H.Yuan, C. Z.Yusa, Y.Zhai, Y.Zhang, Z. P.Zhilich, V.Zhukova, V.2024-01-222024-01-222022-05-162470-0010https://hdl.handle.net/10919/117475We present the first observation of the ωc0→ω-μ+νμ decay and present measurements of the branching fraction ratios of the ωc0→ω-ℓ+νℓ decays compared to the reference mode ωc0→ω-π+, (ℓ=e or μ). This analysis is based on 89.5 fb-1, 711 fb-1, and 121.1 fb-1 data samples collected with the Belle detector at the KEKB asymmetric-energy e+e- collider at the center-of-mass energies of 10.52 GeV, 10.58 GeV, and 10.86 GeV, respectively. The ωc0 signal yields are extracted by fitting Mωℓ and Mωπ spectra. The branching fraction ratios B(ωc0→ω-e+νe)/B(ωc0→ω-π+) and B(ωc0→ω-μ+νμ)/B(ωc0→ω-π+) are measured to be 1.98±0.13(stat)±0.08(syst) and 1.94±0.18(stat)±0.10(syst), respectively. The ratio of B(ωc0→ω-e+νe)/B(ωc0→ω-μ+νμ) is measured to be 1.02±0.10(stat)±0.02(syst), which is consistent with the expectation of lepton flavor universality.7 page(s)application/pdfenIn CopyrightArticle - Refereedhttps://doi.org/10.1103/PhysRevD.105.L0911011059Piilonen, Leo [0000-0001-6836-0748]2470-0029