Aggarwal, L.Ahmed, H.Aihara, H.Akopov, N.Aloisio, A.Ky, N. AnhAsner, D. M.Atmacan, H.Aushev, T.Aushev, V.Bae, H.Bahinipati, S.Bambade, P.Banerjee, SwBansal, S.Barrett, M.Baudot, J.Bauer, M.Baur, A.Beaubien, A.Becker, J.Bennett, J. V.Bernieri, E.Bernlochner, F. U.Bertacchi, V.Bertemes, M.Bertholet, E.Bessner, M.Bettarini, S.Bhardwaj, V.Bhuyan, B.Bianchi, F.Bilka, T.Bilokin, S.Biswas, D.Bodrov, D.Borah, J.Bozek, A.Bracko, M.Briere, R. A.Browder, T. E.Budano, A.Bussino, S.Campajola, M.Cao, L.Casarosa, G.Cecchi, C.Cerasoli, J.Chang, M. -C.Cheaib, R.Cheema, P.Chekelian, V.Cheon, B. G.Chilikin, K.Chirapatpimol, K.Cho, H. -E.Cho, K.Cho, S. -J.Choi, S. -K.Choudhury, S.Cochran, J.Corona, L.Cunliffe, S.Dattola, F.De La Cruz-Burelo, E.De La Motte, S. A.De Nardo, G.De Nuccio, M.De Pietro, G.de Sangro, R.Destefanis, M.Dhamija, R.Di Capua, F.Dingfelder, J.Dolezal, Z.Dong, T. V.Dorigo, M.Dossett, D.Dreyer, S.Dubey, S.Dujany, G.Ecker, P.Eliachevitch, M.Feichtinger, P.Ferber, T.Ferlewicz, D.Fillinger, T.Finocchiaro, G.Fodor, A.Forti, F.Frey, A.Fulsom, B. G.Gabrielli, A.Ganiev, E.Garcia-Hernandez, M.Gaudino, G.Gaur, V.Gaz, A.Gellrich, A.Ghevondyan, G.Giordano, R.Giri, A.Glazov, A.Gobbo, B.Godang, R.Goldenzweig, P.Gradl, W.Grammatico, T.Granderath, S.Graziani, E.Gruberova, Z.Gu, T.Gudkova, K.Halder, S.Hara, T.Hayasaka, K.Hayashii, H.Hazra, S.Hearty, C.Hedges, M. T.de la Cruz, I. HerediaVillanueva, M. HernandezHershenhorn, A.Higuchi, T.Hill, E. C.Hohmann, M.Hsu, C. -L.Iijima, T.Inami, K.Inguglia, G.Ipsita, N.Ishikawa, A.Ito, S.Itoh, R.Iwasaki, M.Jacobs, W. W.Jang, E. -J.Ji, Q. P.Jia, S.Jin, Y.Junkerkalefeld, H.Kaleta, M.Kaliyar, A. B.Karyan, G.Kawasaki, T.Kiesling, C.Kim, C. -H.Kim, D. Y.Kim, K. -H.Kim, Y. -K.Kindo, H.Kinoshita, K.Kodys, P.Kohani, S.Kojima, K.Korobov, A.Korpar, S.Kovalenko, E.Kowalewski, R.Krizan, P.Krokovny, P.Kumar, J.Kumar, R.Kumara, K.Kuzmin, A.Kwon, Y. -J.Lacaprara, S.Lange, J. S.Laurenza, M.Leboucher, R.Le Diberder, F. R.Levit, D.Lewis, P. M.Li, L. K.Libby, J.Liptak, Z.Liu, Q. Y.Liu, Z. Q.Liventsev, D.Longo, S.Lueck, T.Lyu, C.Ma, Y.Maggiora, M.Maharana, S. P.Maiti, R.Maity, S.Manfredi, R.Manoni, E.Manthei, A. C.Mantovano, M.Marinas, C.Martel, L.Martellini, C.Martini, A.Massaccesi, L.Masuda, M.Matsuoka, K.Matvienko, D.Maurya, S. K.McKenna, J. A.Meier, F.Merola, M.Metzner, F.Milesi, M.Miller, C.Miyabayashi, K.Mizuk, R.Mohanty, G. B.Moneta, S.Mrvar, M.Mussa, R.Nakamura, I.Nakamura, K. R.Nakao, M.Nakazawa, Y.Charan, A. NarimaniNaruki, M.Narwal, D.Natochii, A.Nayak, L.Nazaryan, G.Nisar, N. K.Nishida, S.Ono, H.Onuki, Y.Oskin, P.Pakhlov, P.Pakhlova, G.Paladino, A.Panta, A.Pardi, S.Park, H.Park, J.Paschen, B.Passeri, A.Patra, S.Paul, S.Pedlar, T. K.Peruzzi, I.Peschke, R.Pestotnik, R.Piilonen, Leo E.Angioni, G. PinnaPodesta-Lerma, P. L. M.Podobnik, T.Pokharel, S.Polat, L.Praz, C.Prell, S.Prencipe, E.Prim, M. T.Purwar, H.Rad, N.Rados, P.Raeuber, G.Reif, M.Reiter, S.Ripp-Baudot, I.Rizzo, G.Rizzuto, L. B.Rocchetti, P.Roney, J. M.Rostomyan, A.Rout, N.Sanders, D. A.Sandilya, S.Sangal, A.Santelj, L.Sato, Y.Scavino, B.Schwanda, C.Seino, Y.Selce, A.Senyo, K.Sevior, M. E.Sfienti, C.Shan, W.Sharma, C.Shen, C. P.Shillington, T.Shiu, J. -G.Simon, F.Singh, J. B.Skorupa, J.Sobie, R. J.Soffer, A.Sokolov, A.Solovieva, E.Spataro, S.Spruck, B.Staric, M.Stefkova, S.Stroili, R.Sue, Y.Sumihama, M.Sutcliffe, W.Suzuki, S. Y.Svidras, H.Takizawa, M.Tamponi, U.Tanida, K.Taniguchi, N.Tenchini, F.Tiwary, R.Tonelli, D.Torassa, E.Trabelsi, K.Tsaklidis, I.Ueda, I.Uematsu, Y.Uglov, T.Unger, K.Unno, Y.Uno, K.Uno, S.Urquijo, P.Ushiroda, Y.Vahsen, S. E.van Tonder, R.Varner, G. S.Varvell, K. E.Vinokurova, A.Vismaya, V. S.Vitale, L.Vossen, A.Wallner, S.Wang, E.Wang, M. -Z.Wang, X. L.Warburton, A.Watanabe, M.Watanuki, S.Welsch, M.Wessel, C.Won, E.Xu, X. P.Yabsley, B. D.Yamada, S.Yan, W.Yang, S. B.Ye, H.Yin, J. H.Yook, Y. M.Yoshihara, K.Zhai, Y.Zhang, Y.Zhilich, V.Zhou, Q. D.Zhou, X. Y.Zhukova, V. I.Zlebcik, R.2023-12-082023-12-082023-08-022023-08-020031-9007https://hdl.handle.net/10919/117141We present the first measurement of the ratio of branching fractions of inclusive semileptonic B-meson decays, R(Xe/μ)=B(B→Xeν)/B(B→Xμν), a precision test of electron-muon universality, using data corresponding to 189 fb-1 from electron-positron collisions collected with the Belle II detector. In events where the partner B meson is fully reconstructed, we use fits to the lepton momentum spectra above 1.3 GeV/c to obtain R(Xe/μ)=1.007±0.009(stat)±0.019(syst), which is the most precise lepton-universality test of its kind and agrees with the standard-model expectation.7 page(s)PrintenCreative Commons Attribution 4.0 InternationalScience & TechnologyPhysical SciencesPhysics, MultidisciplinaryPhysicsMONTE-CARLOHEAVYBelle II Collaboration5106 Nuclear and Plasma Physics5107 Particle and High Energy Physics4902 Mathematical Physics49 Mathematical Sciences51 Physical Sciences40 EngineeringArticle - Refereedhttps://doi.org/10.1103/PhysRevLett.131.0518041315Piilonen, Leo [0000-0001-6836-0748]375952491079-7114