BELLE2-CONF-PH-2021-012

Belle II Collaboration

#
Measurement of the inclusive semileptonic $B$ meson branching fraction in
$62.8\text{\,}{\mathrm{fb}}^{-1}$ of Belle II data

F. Abudinén  INFN Sezione di Trieste, I-34127 Trieste, Italy  I. Adachi  High
Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan  The
Graduate University for Advanced Studies (SOKENDAI), Hayama 240-0193, Japan
R. Adak  Key Laboratory of Nuclear Physics and Ion-beam Application (MOE) and
Institute of Modern Physics, Fudan University, Shanghai 200443, China  K.
Adamczyk  H. Niewodniczanski Institute of Nuclear Physics, Krakow 31-342,
Poland  L. Aggarwal  Panjab University, Chandigarh 160014, India  P. Ahlburg
University of Bonn, 53115 Bonn, Germany  H. Ahmed  St. Francis Xavier
University, Antigonish, Nova Scotia, B2G 2W5, Canada  J. K. Ahn  Korea
University, Seoul 02841, South Korea  H. Aihara  Department of Physics,
University of Tokyo, Tokyo 113-0033, Japan  N. Akopov  Alikhanyan National
Science Laboratory, Yerevan 0036, Armenia  A. Aloisio  Dipartimento di Scienze
Fisiche, Università di Napoli Federico II, I-80126 Napoli, Italy  INFN Sezione
di Napoli, I-80126 Napoli, Italy  F. Ameli  INFN Sezione di Roma, I-00185
Roma, Italy  L. Andricek  Semiconductor Laboratory of the Max Planck Society,
81739 München, Germany  N. Anh Ky  Institute of Physics, Vietnam Academy of
Science and Technology (VAST), Hanoi, Vietnam  D. M. Asner  Brookhaven
National Laboratory, Upton, New York 11973, U.S.A.  H. Atmacan  University of
Cincinnati, Cincinnati, Ohio 45221, U.S.A.  V. Aulchenko  Budker Institute of
Nuclear Physics SB RAS, Novosibirsk 630090, Russian Federation  Novosibirsk
State University, Novosibirsk 630090, Russian Federation  T. Aushev  National
Research University Higher School of Economics, Moscow 101000, Russian
Federation  V. Aushev  Taras Shevchenko National Univ. of Kiev, Kiev, Ukraine
T. Aziz  Tata Institute of Fundamental Research, Mumbai 400005, India  V. Babu
Deutsches Elektronen–Synchrotron, 22607 Hamburg, Germany  S. Bacher  H.
Niewodniczanski Institute of Nuclear Physics, Krakow 31-342, Poland  H. Bae
Department of Physics, University of Tokyo, Tokyo 113-0033, Japan  S. Baehr
Institut für Experimentelle Teilchenphysik, Karlsruher Institut für
Technologie, 76131 Karlsruhe, Germany  S. Bahinipati  Indian Institute of
Technology Bhubaneswar, Satya Nagar 751007, India  A. M. Bakich  School of
Physics, University of Sydney, New South Wales 2006, Australia  P. Bambade
Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405 Orsay, France  Sw. Banerjee
University of Louisville, Louisville, Kentucky 40292, U.S.A.  S. Bansal
Panjab University, Chandigarh 160014, India  M. Barrett  High Energy
Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan  G. Batignani
Dipartimento di Fisica, Università di Pisa, I-56127 Pisa, Italy  INFN Sezione
di Pisa, I-56127 Pisa, Italy  J. Baudot  Université de Strasbourg, CNRS, IPHC,
UMR 7178, 67037 Strasbourg, France  M. Bauer  Institut für Experimentelle
Teilchenphysik, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany
A. Baur  Deutsches Elektronen–Synchrotron, 22607 Hamburg, Germany  A. Beaulieu
University of Victoria, Victoria, British Columbia, V8W 3P6, Canada  J. Becker
Institut für Experimentelle Teilchenphysik, Karlsruher Institut für
Technologie, 76131 Karlsruhe, Germany  P. K. Behera  Indian Institute of
Technology Madras, Chennai 600036, India  J. V. Bennett  University of
Mississippi, University, Mississippi 38677, U.S.A.  E. Bernieri  INFN Sezione
di Roma Tre, I-00146 Roma, Italy  F. U. Bernlochner  University of Bonn, 53115
Bonn, Germany  M. Bertemes  Institute of High Energy Physics, Vienna 1050,
Austria  E. Bertholet  Tel Aviv University, School of Physics and Astronomy,
Tel Aviv, 69978, Israel  M. Bessner  University of Hawaii, Honolulu, Hawaii
96822, U.S.A.  S. Bettarini  Dipartimento di Fisica, Università di Pisa,
I-56127 Pisa, Italy  INFN Sezione di Pisa, I-56127 Pisa, Italy  V. Bhardwaj
Indian Institute of Science Education and Research Mohali, SAS Nagar, 140306,
India  B. Bhuyan  Indian Institute of Technology Guwahati, Assam 781039, India
F. Bianchi  Dipartimento di Fisica, Università di Torino, I-10125 Torino,
Italy  INFN Sezione di Torino, I-10125 Torino, Italy  T. Bilka  Faculty of
Mathematics and Physics, Charles University, 121 16 Prague, Czech Republic  S.
Bilokin  Ludwig Maximilians University, 80539 Munich, Germany  D. Biswas
University of Louisville, Louisville, Kentucky 40292, U.S.A.  A. Bobrov
Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090, Russian
Federation  Novosibirsk State University, Novosibirsk 630090, Russian
Federation  D. Bodrov  National Research University Higher School of
Economics, Moscow 101000, Russian Federation  P.N. Lebedev Physical Institute
of the Russian Academy of Sciences, Moscow 119991, Russian Federation  A. Bolz
Deutsches Elektronen–Synchrotron, 22607 Hamburg, Germany  A. Bondar  Budker
Institute of Nuclear Physics SB RAS, Novosibirsk 630090, Russian Federation
Novosibirsk State University, Novosibirsk 630090, Russian Federation  G.
Bonvicini  Wayne State University, Detroit, Michigan 48202, U.S.A.  A. Bozek
H. Niewodniczanski Institute of Nuclear Physics, Krakow 31-342, Poland  M.
Bračko  Faculty of Chemistry and Chemical Engineering, University of Maribor,
2000 Maribor, Slovenia  J. Stefan Institute, 1000 Ljubljana, Slovenia  P.
Branchini  INFN Sezione di Roma Tre, I-00146 Roma, Italy  N. Braun  Institut
für Experimentelle Teilchenphysik, Karlsruher Institut für Technologie, 76131
Karlsruhe, Germany  R. A. Briere  Carnegie Mellon University, Pittsburgh,
Pennsylvania 15213, U.S.A.  T. E. Browder  University of Hawaii, Honolulu,
Hawaii 96822, U.S.A.  D. N. Brown  University of Louisville, Louisville,
Kentucky 40292, U.S.A.  A. Budano  INFN Sezione di Roma Tre, I-00146 Roma,
Italy  L. Burmistrov  Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405
Orsay, France  S. Bussino  Dipartimento di Matematica e Fisica, Università di
Roma Tre, I-00146 Roma, Italy  INFN Sezione di Roma Tre, I-00146 Roma, Italy
M. Campajola  Dipartimento di Scienze Fisiche, Università di Napoli Federico
II, I-80126 Napoli, Italy  INFN Sezione di Napoli, I-80126 Napoli, Italy  L.
Cao  Deutsches Elektronen–Synchrotron, 22607 Hamburg, Germany  G. Casarosa
Dipartimento di Fisica, Università di Pisa, I-56127 Pisa, Italy  INFN Sezione
di Pisa, I-56127 Pisa, Italy  C. Cecchi  Dipartimento di Fisica, Università di
Perugia, I-06123 Perugia, Italy  INFN Sezione di Perugia, I-06123 Perugia,
Italy  D. Červenkov  Faculty of Mathematics and Physics, Charles University,
121 16 Prague, Czech Republic  M.-C. Chang  Department of Physics, Fu Jen
Catholic University, Taipei 24205, Taiwan  P. Chang  Department of Physics,
National Taiwan University, Taipei 10617, Taiwan  R. Cheaib  Deutsches
Elektronen–Synchrotron, 22607 Hamburg, Germany  P. Cheema  School of Physics,
University of Sydney, New South Wales 2006, Australia  V. Chekelian  Max-
Planck-Institut für Physik, 80805 München, Germany  C. Chen  Iowa State
University, Ames, Iowa 50011, U.S.A.  Y. Q. Chen  University of Science and
Technology of China, Hefei 230026, China  Y.-T. Chen  Department of Physics,
National Taiwan University, Taipei 10617, Taiwan  B. G. Cheon  Department of
Physics and Institute of Natural Sciences, Hanyang University, Seoul 04763,
South Korea  K. Chilikin  P.N. Lebedev Physical Institute of the Russian
Academy of Sciences, Moscow 119991, Russian Federation  K. Chirapatpimol
Chiang Mai University, Chiang Mai 50202, Thailand  H.-E. Cho  Department of
Physics and Institute of Natural Sciences, Hanyang University, Seoul 04763,
South Korea  K. Cho  Korea Institute of Science and Technology Information,
Daejeon 34141, South Korea  S.-J. Cho  Yonsei University, Seoul 03722, South
Korea  S.-K. Choi  Chung-Ang University, Seoul 06974, South Korea  S.
Choudhury  Iowa State University, Ames, Iowa 50011, U.S.A.  D. Cinabro  Wayne
State University, Detroit, Michigan 48202, U.S.A.  L. Corona  Dipartimento di
Fisica, Università di Pisa, I-56127 Pisa, Italy  INFN Sezione di Pisa, I-56127
Pisa, Italy  L. M. Cremaldi  University of Mississippi, University,
Mississippi 38677, U.S.A.  D. Cuesta  Université de Strasbourg, CNRS, IPHC,
UMR 7178, 67037 Strasbourg, France  S. Cunliffe  Deutsches
Elektronen–Synchrotron, 22607 Hamburg, Germany  T. Czank  Kavli Institute for
the Physics and Mathematics of the Universe (WPI), University of Tokyo,
Kashiwa 277-8583, Japan  N. Dash  Indian Institute of Technology Madras,
Chennai 600036, India  F. Dattola  Deutsches Elektronen–Synchrotron, 22607
Hamburg, Germany  E. De La Cruz-Burelo  Centro de Investigacion y de Estudios
Avanzados del Instituto Politecnico Nacional, Mexico City 07360, Mexico  G. de
Marino  Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405 Orsay, France  G.
De Nardo  Dipartimento di Scienze Fisiche, Università di Napoli Federico II,
I-80126 Napoli, Italy  INFN Sezione di Napoli, I-80126 Napoli, Italy  M. De
Nuccio  Deutsches Elektronen–Synchrotron, 22607 Hamburg, Germany  G. De Pietro
INFN Sezione di Roma Tre, I-00146 Roma, Italy  R. de Sangro  INFN Laboratori
Nazionali di Frascati, I-00044 Frascati, Italy  B. Deschamps  University of
Bonn, 53115 Bonn, Germany  M. Destefanis  Dipartimento di Fisica, Università
di Torino, I-10125 Torino, Italy  INFN Sezione di Torino, I-10125 Torino,
Italy  S. Dey  Tel Aviv University, School of Physics and Astronomy, Tel Aviv,
69978, Israel  A. De Yta-Hernandez  Centro de Investigacion y de Estudios
Avanzados del Instituto Politecnico Nacional, Mexico City 07360, Mexico  R.
Dhamija  Indian Institute of Technology Hyderabad, Telangana 502285, India  A.
Di Canto  Brookhaven National Laboratory, Upton, New York 11973, U.S.A.  F. Di
Capua  Dipartimento di Scienze Fisiche, Università di Napoli Federico II,
I-80126 Napoli, Italy  INFN Sezione di Napoli, I-80126 Napoli, Italy  S. Di
Carlo  Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405 Orsay, France  J.
Dingfelder  University of Bonn, 53115 Bonn, Germany  Z. Doležal  Faculty of
Mathematics and Physics, Charles University, 121 16 Prague, Czech Republic  I.
Domínguez Jiménez  Universidad Autonoma de Sinaloa, Sinaloa 80000, Mexico  T.
V. Dong  Institute of Theoretical and Applied Research (ITAR), Duy Tan
University, Hanoi 100000, Vietnam  M. Dorigo  INFN Sezione di Trieste, I-34127
Trieste, Italy  K. Dort  Justus-Liebig-Universität Gießen, 35392 Gießen,
Germany  D. Dossett  School of Physics, University of Melbourne, Victoria
3010, Australia  S. Dubey  University of Hawaii, Honolulu, Hawaii 96822,
U.S.A.  S. Duell  University of Bonn, 53115 Bonn, Germany  G. Dujany
Université de Strasbourg, CNRS, IPHC, UMR 7178, 67037 Strasbourg, France  P.
Ecker  Institut für Experimentelle Teilchenphysik, Karlsruher Institut für
Technologie, 76131 Karlsruhe, Germany  M. Eliachevitch  University of Bonn,
53115 Bonn, Germany  D. Epifanov  Budker Institute of Nuclear Physics SB RAS,
Novosibirsk 630090, Russian Federation  Novosibirsk State University,
Novosibirsk 630090, Russian Federation  P. Feichtinger  Institute of High
Energy Physics, Vienna 1050, Austria  T. Ferber  Institut für Experimentelle
Teilchenphysik, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany
D. Ferlewicz  School of Physics, University of Melbourne, Victoria 3010,
Australia  T. Fillinger  Université de Strasbourg, CNRS, IPHC, UMR 7178, 67037
Strasbourg, France  G. Finocchiaro  INFN Laboratori Nazionali di Frascati,
I-00044 Frascati, Italy  S. Fiore  INFN Sezione di Roma, I-00185 Roma, Italy
P. Fischer  University of Heidelberg, 68131 Mannheim, Germany  K. Flood
University of Hawaii, Honolulu, Hawaii 96822, U.S.A.  A. Fodor  McGill
University, Montréal, Québec, H3A 2T8, Canada  F. Forti  Dipartimento di
Fisica, Università di Pisa, I-56127 Pisa, Italy  INFN Sezione di Pisa, I-56127
Pisa, Italy  A. Frey  II. Physikalisches Institut, Georg-August-Universität
Göttingen, 37073 Göttingen, Germany  M. Friedl  Institute of High Energy
Physics, Vienna 1050, Austria  B. G. Fulsom  Pacific Northwest National
Laboratory, Richland, Washington 99352, U.S.A.  M. Gabriel  Max-Planck-
Institut für Physik, 80805 München, Germany  A. Gabrielli  Dipartimento di
Fisica, Università di Trieste, I-34127 Trieste, Italy  INFN Sezione di
Trieste, I-34127 Trieste, Italy  N. Gabyshev  Budker Institute of Nuclear
Physics SB RAS, Novosibirsk 630090, Russian Federation  Novosibirsk State
University, Novosibirsk 630090, Russian Federation  E. Ganiev  Dipartimento di
Fisica, Università di Trieste, I-34127 Trieste, Italy  INFN Sezione di
Trieste, I-34127 Trieste, Italy  M. Garcia-Hernandez  Centro de Investigacion
y de Estudios Avanzados del Instituto Politecnico Nacional, Mexico City 07360,
Mexico  R. Garg  Panjab University, Chandigarh 160014, India  A. Garmash
Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090, Russian
Federation  Novosibirsk State University, Novosibirsk 630090, Russian
Federation  V. Gaur  Virginia Polytechnic Institute and State University,
Blacksburg, Virginia 24061, U.S.A.  A. Gaz  Dipartimento di Fisica e
Astronomia, Università di Padova, I-35131 Padova, Italy  INFN Sezione di
Padova, I-35131 Padova, Italy  U. Gebauer  II. Physikalisches Institut, Georg-
August-Universität Göttingen, 37073 Göttingen, Germany  A. Gellrich  Deutsches
Elektronen–Synchrotron, 22607 Hamburg, Germany  J. Gemmler  Institut für
Experimentelle Teilchenphysik, Karlsruher Institut für Technologie, 76131
Karlsruhe, Germany  T. Geßler  Justus-Liebig-Universität Gießen, 35392 Gießen,
Germany  D. Getzkow  Justus-Liebig-Universität Gießen, 35392 Gießen, Germany
G. Giakoustidis  University of Bonn, 53115 Bonn, Germany  R. Giordano
Dipartimento di Scienze Fisiche, Università di Napoli Federico II, I-80126
Napoli, Italy  INFN Sezione di Napoli, I-80126 Napoli, Italy  A. Giri  Indian
Institute of Technology Hyderabad, Telangana 502285, India  A. Glazov
Deutsches Elektronen–Synchrotron, 22607 Hamburg, Germany  B. Gobbo  INFN
Sezione di Trieste, I-34127 Trieste, Italy  R. Godang  University of South
Alabama, Mobile, Alabama 36688, U.S.A.  P. Goldenzweig  Institut für
Experimentelle Teilchenphysik, Karlsruher Institut für Technologie, 76131
Karlsruhe, Germany  B. Golob  Faculty of Mathematics and Physics, University
of Ljubljana, 1000 Ljubljana, Slovenia  J. Stefan Institute, 1000 Ljubljana,
Slovenia  P. Gomis  Instituto de Fisica Corpuscular, Paterna 46980, Spain  G.
Gong  University of Science and Technology of China, Hefei 230026, China  P.
Grace  Department of Physics, University of Adelaide, Adelaide, South
Australia 5005, Australia  W. Gradl  Institut für Kernphysik, Johannes
Gutenberg-Universität Mainz, D-55099 Mainz, Germany  E. Graziani  INFN Sezione
di Roma Tre, I-00146 Roma, Italy  D. Greenwald  Department of Physics,
Technische Universität München, 85748 Garching, Germany  T. Gu  University of
Pittsburgh, Pittsburgh, Pennsylvania 15260, U.S.A.  Y. Guan  University of
Cincinnati, Cincinnati, Ohio 45221, U.S.A.  K. Gudkova  Budker Institute of
Nuclear Physics SB RAS, Novosibirsk 630090, Russian Federation  Novosibirsk
State University, Novosibirsk 630090, Russian Federation  J. Guilliams
University of Mississippi, University, Mississippi 38677, U.S.A.  C.
Hadjivasiliou  Pacific Northwest National Laboratory, Richland, Washington
99352, U.S.A.  S. Halder  Tata Institute of Fundamental Research, Mumbai
400005, India  K. Hara  High Energy Accelerator Research Organization (KEK),
Tsukuba 305-0801, Japan  The Graduate University for Advanced Studies
(SOKENDAI), Hayama 240-0193, Japan  T. Hara  High Energy Accelerator Research
Organization (KEK), Tsukuba 305-0801, Japan  The Graduate University for
Advanced Studies (SOKENDAI), Hayama 240-0193, Japan  O. Hartbrich  University
of Hawaii, Honolulu, Hawaii 96822, U.S.A.  K. Hayasaka  Niigata University,
Niigata 950-2181, Japan  H. Hayashii  Nara Women’s University, Nara 630-8506,
Japan  S. Hazra  Tata Institute of Fundamental Research, Mumbai 400005, India
C. Hearty  University of British Columbia, Vancouver, British Columbia, V6T
1Z1, Canada  Institute of Particle Physics (Canada), Victoria, British
Columbia V8W 2Y2, Canada  M. T. Hedges  University of Hawaii, Honolulu, Hawaii
96822, U.S.A.  I. Heredia de la Cruz  Centro de Investigacion y de Estudios
Avanzados del Instituto Politecnico Nacional, Mexico City 07360, Mexico
Consejo Nacional de Ciencia y Tecnología, Mexico City 03940, Mexico  M.
Hernández Villanueva  Deutsches Elektronen–Synchrotron, 22607 Hamburg, Germany
A. Hershenhorn  University of British Columbia, Vancouver, British Columbia,
V6T 1Z1, Canada  T. Higuchi  Kavli Institute for the Physics and Mathematics
of the Universe (WPI), University of Tokyo, Kashiwa 277-8583, Japan  E. C.
Hill  University of British Columbia, Vancouver, British Columbia, V6T 1Z1,
Canada  H. Hirata  Graduate School of Science, Nagoya University, Nagoya
464-8602, Japan  M. Hoek  Institut für Kernphysik, Johannes Gutenberg-
Universität Mainz, D-55099 Mainz, Germany  M. Hohmann  School of Physics,
University of Melbourne, Victoria 3010, Australia  S. Hollitt  Department of
Physics, University of Adelaide, Adelaide, South Australia 5005, Australia  T.
Hotta  Research Center for Nuclear Physics, Osaka University, Osaka 567-0047,
Japan  C.-L. Hsu  School of Physics, University of Sydney, New South Wales
2006, Australia  Y. Hu  Institute of High Energy Physics, Chinese Academy of
Sciences, Beijing 100049, China  K. Huang  Department of Physics, National
Taiwan University, Taipei 10617, Taiwan  T. Humair  Max-Planck-Institut für
Physik, 80805 München, Germany  T. Iijima  Graduate School of Science, Nagoya
University, Nagoya 464-8602, Japan  Kobayashi-Maskawa Institute, Nagoya
University, Nagoya 464-8602, Japan  K. Inami  Graduate School of Science,
Nagoya University, Nagoya 464-8602, Japan  G. Inguglia  Institute of High
Energy Physics, Vienna 1050, Austria  J. Irakkathil Jabbar  Institut für
Experimentelle Teilchenphysik, Karlsruher Institut für Technologie, 76131
Karlsruhe, Germany  A. Ishikawa  High Energy Accelerator Research Organization
(KEK), Tsukuba 305-0801, Japan  The Graduate University for Advanced Studies
(SOKENDAI), Hayama 240-0193, Japan  R. Itoh  High Energy Accelerator Research
Organization (KEK), Tsukuba 305-0801, Japan  The Graduate University for
Advanced Studies (SOKENDAI), Hayama 240-0193, Japan  M. Iwasaki  Osaka City
University, Osaka 558-8585, Japan  Y. Iwasaki  High Energy Accelerator
Research Organization (KEK), Tsukuba 305-0801, Japan  S. Iwata  Tokyo
Metropolitan University, Tokyo 192-0397, Japan  P. Jackson  Department of
Physics, University of Adelaide, Adelaide, South Australia 5005, Australia  W.
W. Jacobs  Indiana University, Bloomington, Indiana 47408, U.S.A.  I. Jaegle
University of Florida, Gainesville, Florida 32611, U.S.A.  D. E. Jaffe
Brookhaven National Laboratory, Upton, New York 11973, U.S.A.  E.-J. Jang
Gyeongsang National University, Jinju 52828, South Korea  M. Jeandron
University of Mississippi, University, Mississippi 38677, U.S.A.  H. B. Jeon
Kyungpook National University, Daegu 41566, South Korea  S. Jia  Key
Laboratory of Nuclear Physics and Ion-beam Application (MOE) and Institute of
Modern Physics, Fudan University, Shanghai 200443, China  Y. Jin  INFN Sezione
di Trieste, I-34127 Trieste, Italy  C. Joo  Kavli Institute for the Physics
and Mathematics of the Universe (WPI), University of Tokyo, Kashiwa 277-8583,
Japan  K. K. Joo  Chonnam National University, Gwangju 61186, South Korea  H.
Junkerkalefeld  University of Bonn, 53115 Bonn, Germany  I. Kadenko  Taras
Shevchenko National Univ. of Kiev, Kiev, Ukraine  J. Kahn  Institut für
Experimentelle Teilchenphysik, Karlsruher Institut für Technologie, 76131
Karlsruhe, Germany  H. Kakuno  Tokyo Metropolitan University, Tokyo 192-0397,
Japan  M. Kaleta  H. Niewodniczanski Institute of Nuclear Physics, Krakow
31-342, Poland  A. B. Kaliyar  Tata Institute of Fundamental Research, Mumbai
400005, India  J. Kandra  Faculty of Mathematics and Physics, Charles
University, 121 16 Prague, Czech Republic  K. H. Kang  Kavli Institute for the
Physics and Mathematics of the Universe (WPI), University of Tokyo, Kashiwa
277-8583, Japan  P. Kapusta  H. Niewodniczanski Institute of Nuclear Physics,
Krakow 31-342, Poland  R. Karl  Deutsches Elektronen–Synchrotron, 22607
Hamburg, Germany  G. Karyan  Alikhanyan National Science Laboratory, Yerevan
0036, Armenia  Y. Kato  Graduate School of Science, Nagoya University, Nagoya
464-8602, Japan  Kobayashi-Maskawa Institute, Nagoya University, Nagoya
464-8602, Japan  H. Kawai  Chiba University, Chiba 263-8522, Japan  T.
Kawasaki  Kitasato University, Sagamihara 252-0373, Japan  C. Ketter
University of Hawaii, Honolulu, Hawaii 96822, U.S.A.  H. Kichimi  High Energy
Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan  C. Kiesling
Max-Planck-Institut für Physik, 80805 München, Germany  B. H. Kim  Seoul
National University, Seoul 08826, South Korea  C.-H. Kim  Department of
Physics and Institute of Natural Sciences, Hanyang University, Seoul 04763,
South Korea  D. Y. Kim  Soongsil University, Seoul 06978, South Korea  H. J.
Kim  Kyungpook National University, Daegu 41566, South Korea  K.-H. Kim
Yonsei University, Seoul 03722, South Korea  K. Kim  Korea University, Seoul
02841, South Korea  S.-H. Kim  Seoul National University, Seoul 08826, South
Korea  Y.-K. Kim  Yonsei University, Seoul 03722, South Korea  Y. Kim  Korea
University, Seoul 02841, South Korea  T. D. Kimmel  Virginia Polytechnic
Institute and State University, Blacksburg, Virginia 24061, U.S.A.  H. Kindo
High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan
The Graduate University for Advanced Studies (SOKENDAI), Hayama 240-0193,
Japan  K. Kinoshita  University of Cincinnati, Cincinnati, Ohio 45221, U.S.A.
C. Kleinwort  Deutsches Elektronen–Synchrotron, 22607 Hamburg, Germany  B.
Knysh  Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405 Orsay, France  P.
Kodyš  Faculty of Mathematics and Physics, Charles University, 121 16 Prague,
Czech Republic  T. Koga  High Energy Accelerator Research Organization (KEK),
Tsukuba 305-0801, Japan  S. Kohani  University of Hawaii, Honolulu, Hawaii
96822, U.S.A.  I. Komarov  Deutsches Elektronen–Synchrotron, 22607 Hamburg,
Germany  T. Konno  Kitasato University, Sagamihara 252-0373, Japan  A. Korobov
Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090, Russian
Federation  Novosibirsk State University, Novosibirsk 630090, Russian
Federation  S. Korpar  Faculty of Chemistry and Chemical Engineering,
University of Maribor, 2000 Maribor, Slovenia  J. Stefan Institute, 1000
Ljubljana, Slovenia  N. Kovalchuk  Deutsches Elektronen–Synchrotron, 22607
Hamburg, Germany  E. Kovalenko  Budker Institute of Nuclear Physics SB RAS,
Novosibirsk 630090, Russian Federation  Novosibirsk State University,
Novosibirsk 630090, Russian Federation  R. Kowalewski  University of Victoria,
Victoria, British Columbia, V8W 3P6, Canada  T. M. G. Kraetzschmar  Max-
Planck-Institut für Physik, 80805 München, Germany  F. Krinner  Max-Planck-
Institut für Physik, 80805 München, Germany  P. Križan  Faculty of Mathematics
and Physics, University of Ljubljana, 1000 Ljubljana, Slovenia  J. Stefan
Institute, 1000 Ljubljana, Slovenia  R. Kroeger  University of Mississippi,
University, Mississippi 38677, U.S.A.  J. F. Krohn  School of Physics,
University of Melbourne, Victoria 3010, Australia  P. Krokovny  Budker
Institute of Nuclear Physics SB RAS, Novosibirsk 630090, Russian Federation
Novosibirsk State University, Novosibirsk 630090, Russian Federation  H.
Krüger  University of Bonn, 53115 Bonn, Germany  W. Kuehn  Justus-Liebig-
Universität Gießen, 35392 Gießen, Germany  T. Kuhr  Ludwig Maximilians
University, 80539 Munich, Germany  J. Kumar  Carnegie Mellon University,
Pittsburgh, Pennsylvania 15213, U.S.A.  M. Kumar  Malaviya National Institute
of Technology Jaipur, Jaipur 302017, India  R. Kumar  Punjab Agricultural
University, Ludhiana 141004, India  K. Kumara  Wayne State University,
Detroit, Michigan 48202, U.S.A.  T. Kumita  Tokyo Metropolitan University,
Tokyo 192-0397, Japan  T. Kunigo  High Energy Accelerator Research
Organization (KEK), Tsukuba 305-0801, Japan  M. Künzel  Deutsches
Elektronen–Synchrotron, 22607 Hamburg, Germany  Ludwig Maximilians University,
80539 Munich, Germany  S. Kurz  Deutsches Elektronen–Synchrotron, 22607
Hamburg, Germany  A. Kuzmin  Budker Institute of Nuclear Physics SB RAS,
Novosibirsk 630090, Russian Federation  Novosibirsk State University,
Novosibirsk 630090, Russian Federation  P. Kvasnička  Faculty of Mathematics
and Physics, Charles University, 121 16 Prague, Czech Republic  Y.-J. Kwon
Yonsei University, Seoul 03722, South Korea  S. Lacaprara  INFN Sezione di
Padova, I-35131 Padova, Italy  Y.-T. Lai  Kavli Institute for the Physics and
Mathematics of the Universe (WPI), University of Tokyo, Kashiwa 277-8583,
Japan  C. La Licata  Kavli Institute for the Physics and Mathematics of the
Universe (WPI), University of Tokyo, Kashiwa 277-8583, Japan  K. Lalwani
Malaviya National Institute of Technology Jaipur, Jaipur 302017, India  T. Lam
Virginia Polytechnic Institute and State University, Blacksburg, Virginia
24061, U.S.A.  L. Lanceri  INFN Sezione di Trieste, I-34127 Trieste, Italy  J.
S. Lange  Justus-Liebig-Universität Gießen, 35392 Gießen, Germany  M. Laurenza
Dipartimento di Matematica e Fisica, Università di Roma Tre, I-00146 Roma,
Italy  INFN Sezione di Roma Tre, I-00146 Roma, Italy  K. Lautenbach  Aix
Marseille Université, CNRS/IN2P3, CPPM, 13288 Marseille, France  P. J. Laycock
Brookhaven National Laboratory, Upton, New York 11973, U.S.A.  R. Leboucher
Aix Marseille Université, CNRS/IN2P3, CPPM, 13288 Marseille, France  F. R. Le
Diberder  Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405 Orsay, France
I.-S. Lee  Department of Physics and Institute of Natural Sciences, Hanyang
University, Seoul 04763, South Korea  S. C. Lee  Kyungpook National
University, Daegu 41566, South Korea  P. Leitl  Max-Planck-Institut für
Physik, 80805 München, Germany  D. Levit  High Energy Accelerator Research
Organization (KEK), Tsukuba 305-0801, Japan  P. M. Lewis  University of Bonn,
53115 Bonn, Germany  C. Li  Liaoning Normal University, Dalian 116029, China
L. K. Li  University of Cincinnati, Cincinnati, Ohio 45221, U.S.A.  S. X. Li
Key Laboratory of Nuclear Physics and Ion-beam Application (MOE) and Institute
of Modern Physics, Fudan University, Shanghai 200443, China  Y. B. Li  Key
Laboratory of Nuclear Physics and Ion-beam Application (MOE) and Institute of
Modern Physics, Fudan University, Shanghai 200443, China  J. Libby  Indian
Institute of Technology Madras, Chennai 600036, India  K. Lieret  Ludwig
Maximilians University, 80539 Munich, Germany  J. Lin  Department of Physics,
National Taiwan University, Taipei 10617, Taiwan  Z. Liptak  Hiroshima
University, Higashi-Hiroshima, Hiroshima 739-8530, Japan  Q. Y. Liu  Deutsches
Elektronen–Synchrotron, 22607 Hamburg, Germany  Z. A. Liu  Institute of High
Energy Physics, Chinese Academy of Sciences, Beijing 100049, China  D.
Liventsev  Wayne State University, Detroit, Michigan 48202, U.S.A.  High
Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan  S.
Longo  Deutsches Elektronen–Synchrotron, 22607 Hamburg, Germany  A. Loos
University of South Carolina, Columbia, South Carolina 29208, U.S.A.  A. Lozar
J. Stefan Institute, 1000 Ljubljana, Slovenia  P. Lu  Department of Physics,
National Taiwan University, Taipei 10617, Taiwan  T. Lueck  Ludwig Maximilians
University, 80539 Munich, Germany  F. Luetticke  University of Bonn, 53115
Bonn, Germany  T. Luo  Key Laboratory of Nuclear Physics and Ion-beam
Application (MOE) and Institute of Modern Physics, Fudan University, Shanghai
200443, China  C. Lyu  University of Bonn, 53115 Bonn, Germany  C. MacQueen
School of Physics, University of Melbourne, Victoria 3010, Australia  M.
Maggiora  Dipartimento di Fisica, Università di Torino, I-10125 Torino, Italy
INFN Sezione di Torino, I-10125 Torino, Italy  R. Maiti  Institute of High
Energy Physics, Vienna 1050, Austria  S. Maity  Indian Institute of Technology
Bhubaneswar, Satya Nagar 751007, India  R. Manfredi  Dipartimento di Fisica,
Università di Trieste, I-34127 Trieste, Italy  INFN Sezione di Trieste,
I-34127 Trieste, Italy  E. Manoni  INFN Sezione di Perugia, I-06123 Perugia,
Italy  S. Marcello  Dipartimento di Fisica, Università di Torino, I-10125
Torino, Italy  INFN Sezione di Torino, I-10125 Torino, Italy  C. Marinas
Instituto de Fisica Corpuscular, Paterna 46980, Spain  L. Martel  Université
de Strasbourg, CNRS, IPHC, UMR 7178, 67037 Strasbourg, France  A. Martini
Deutsches Elektronen–Synchrotron, 22607 Hamburg, Germany  L. Massaccesi
Dipartimento di Fisica, Università di Pisa, I-56127 Pisa, Italy  INFN Sezione
di Pisa, I-56127 Pisa, Italy  M. Masuda  Earthquake Research Institute,
University of Tokyo, Tokyo 113-0032, Japan  Research Center for Nuclear
Physics, Osaka University, Osaka 567-0047, Japan  T. Matsuda  University of
Miyazaki, Miyazaki 889-2192, Japan  K. Matsuoka  High Energy Accelerator
Research Organization (KEK), Tsukuba 305-0801, Japan  D. Matvienko  Budker
Institute of Nuclear Physics SB RAS, Novosibirsk 630090, Russian Federation
P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Moscow
119991, Russian Federation  Novosibirsk State University, Novosibirsk 630090,
Russian Federation  J. A. McKenna  University of British Columbia, Vancouver,
British Columbia, V6T 1Z1, Canada  J. McNeil  University of Florida,
Gainesville, Florida 32611, U.S.A.  F. Meggendorfer  Max-Planck-Institut für
Physik, 80805 München, Germany  J. C. Mei  Key Laboratory of Nuclear Physics
and Ion-beam Application (MOE) and Institute of Modern Physics, Fudan
University, Shanghai 200443, China  F. Meier  Duke University, Durham, North
Carolina 27708, U.S.A.  M. Merola  Dipartimento di Scienze Fisiche, Università
di Napoli Federico II, I-80126 Napoli, Italy  INFN Sezione di Napoli, I-80126
Napoli, Italy  F. Metzner  Institut für Experimentelle Teilchenphysik,
Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany  M. Milesi
School of Physics, University of Melbourne, Victoria 3010, Australia  C.
Miller  University of Victoria, Victoria, British Columbia, V8W 3P6, Canada
K. Miyabayashi  Nara Women’s University, Nara 630-8506, Japan  H. Miyake  High
Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan  The
Graduate University for Advanced Studies (SOKENDAI), Hayama 240-0193, Japan
H. Miyata  Niigata University, Niigata 950-2181, Japan  R. Mizuk  P.N. Lebedev
Physical Institute of the Russian Academy of Sciences, Moscow 119991, Russian
Federation  National Research University Higher School of Economics, Moscow
101000, Russian Federation  K. Azmi  National Centre for Particle Physics,
University Malaya, 50603 Kuala Lumpur, Malaysia  G. B. Mohanty  Tata Institute
of Fundamental Research, Mumbai 400005, India  N. Molina-Gonzalez  Centro de
Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional,
Mexico City 07360, Mexico  H. Moon  Korea University, Seoul 02841, South Korea
T. Moon  Seoul National University, Seoul 08826, South Korea  J. A. Mora
Grimaldo  Department of Physics, University of Tokyo, Tokyo 113-0033, Japan
T. Morii  Kavli Institute for the Physics and Mathematics of the Universe
(WPI), University of Tokyo, Kashiwa 277-8583, Japan  H.-G. Moser  Max-Planck-
Institut für Physik, 80805 München, Germany  M. Mrvar  Institute of High
Energy Physics, Vienna 1050, Austria  F. Mueller  Max-Planck-Institut für
Physik, 80805 München, Germany  F. J. Müller  Deutsches
Elektronen–Synchrotron, 22607 Hamburg, Germany  Th. Muller  Institut für
Experimentelle Teilchenphysik, Karlsruher Institut für Technologie, 76131
Karlsruhe, Germany  G. Muroyama  Graduate School of Science, Nagoya
University, Nagoya 464-8602, Japan  C. Murphy  Kavli Institute for the Physics
and Mathematics of the Universe (WPI), University of Tokyo, Kashiwa 277-8583,
Japan  R. Mussa  INFN Sezione di Torino, I-10125 Torino, Italy  I. Nakamura
High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan
The Graduate University for Advanced Studies (SOKENDAI), Hayama 240-0193,
Japan  K. R. Nakamura  High Energy Accelerator Research Organization (KEK),
Tsukuba 305-0801, Japan  The Graduate University for Advanced Studies
(SOKENDAI), Hayama 240-0193, Japan  E. Nakano  Osaka City University, Osaka
558-8585, Japan  M. Nakao  High Energy Accelerator Research Organization
(KEK), Tsukuba 305-0801, Japan  The Graduate University for Advanced Studies
(SOKENDAI), Hayama 240-0193, Japan  H. Nakayama  High Energy Accelerator
Research Organization (KEK), Tsukuba 305-0801, Japan  The Graduate University
for Advanced Studies (SOKENDAI), Hayama 240-0193, Japan  H. Nakazawa
Department of Physics, National Taiwan University, Taipei 10617, Taiwan  M.
Naruki  Kyoto University, Kyoto 606-8501, Japan  Z. Natkaniec  H.
Niewodniczanski Institute of Nuclear Physics, Krakow 31-342, Poland  A.
Natochii  University of Hawaii, Honolulu, Hawaii 96822, U.S.A.  L. Nayak
Indian Institute of Technology Hyderabad, Telangana 502285, India  M. Nayak
Tel Aviv University, School of Physics and Astronomy, Tel Aviv, 69978, Israel
G. Nazaryan  Alikhanyan National Science Laboratory, Yerevan 0036, Armenia  D.
Neverov  Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
C. Niebuhr  Deutsches Elektronen–Synchrotron, 22607 Hamburg, Germany  M.
Niiyama  Kyoto Sangyo University, Kyoto 603-8555, Japan  J. Ninkovic
Semiconductor Laboratory of the Max Planck Society, 81739 München, Germany  N.
K. Nisar  Brookhaven National Laboratory, Upton, New York 11973, U.S.A.  S.
Nishida  High Energy Accelerator Research Organization (KEK), Tsukuba
305-0801, Japan  The Graduate University for Advanced Studies (SOKENDAI),
Hayama 240-0193, Japan  K. Nishimura  University of Hawaii, Honolulu, Hawaii
96822, U.S.A.  M. Nishimura  High Energy Accelerator Research Organization
(KEK), Tsukuba 305-0801, Japan  M. H. A. Nouxman  National Centre for Particle
Physics, University Malaya, 50603 Kuala Lumpur, Malaysia  B. Oberhof  INFN
Laboratori Nazionali di Frascati, I-00044 Frascati, Italy  K. Ogawa  Niigata
University, Niigata 950-2181, Japan  S. Ogawa  Toho University, Funabashi
274-8510, Japan  S. L. Olsen  Chung-Ang University, Seoul 06974, South Korea
Y. Onishchuk  Taras Shevchenko National Univ. of Kiev, Kiev, Ukraine  H. Ono
Niigata University, Niigata 950-2181, Japan  Y. Onuki  Department of Physics,
University of Tokyo, Tokyo 113-0033, Japan  P. Oskin  P.N. Lebedev Physical
Institute of the Russian Academy of Sciences, Moscow 119991, Russian
Federation  E. R. Oxford  Carnegie Mellon University, Pittsburgh, Pennsylvania
15213, U.S.A.  H. Ozaki  High Energy Accelerator Research Organization (KEK),
Tsukuba 305-0801, Japan  The Graduate University for Advanced Studies
(SOKENDAI), Hayama 240-0193, Japan  P. Pakhlov  P.N. Lebedev Physical
Institute of the Russian Academy of Sciences, Moscow 119991, Russian
Federation  Moscow Physical Engineering Institute, Moscow 115409, Russian
Federation  G. Pakhlova  National Research University Higher School of
Economics, Moscow 101000, Russian Federation  P.N. Lebedev Physical Institute
of the Russian Academy of Sciences, Moscow 119991, Russian Federation  A.
Paladino  Dipartimento di Fisica, Università di Pisa, I-56127 Pisa, Italy
INFN Sezione di Pisa, I-56127 Pisa, Italy  T. Pang  University of Pittsburgh,
Pittsburgh, Pennsylvania 15260, U.S.A.  A. Panta  University of Mississippi,
University, Mississippi 38677, U.S.A.  E. Paoloni  Dipartimento di Fisica,
Università di Pisa, I-56127 Pisa, Italy  INFN Sezione di Pisa, I-56127 Pisa,
Italy  S. Pardi  INFN Sezione di Napoli, I-80126 Napoli, Italy  H. Park
Kyungpook National University, Daegu 41566, South Korea  S.-H. Park  High
Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan  B.
Paschen  University of Bonn, 53115 Bonn, Germany  A. Passeri  INFN Sezione di
Roma Tre, I-00146 Roma, Italy  A. Pathak  University of Louisville,
Louisville, Kentucky 40292, U.S.A.  S. Patra  Indian Institute of Science
Education and Research Mohali, SAS Nagar, 140306, India  S. Paul  Department
of Physics, Technische Universität München, 85748 Garching, Germany  T. K.
Pedlar  Luther College, Decorah, Iowa 52101, U.S.A.  I. Peruzzi  INFN
Laboratori Nazionali di Frascati, I-00044 Frascati, Italy  R. Peschke
University of Hawaii, Honolulu, Hawaii 96822, U.S.A.  R. Pestotnik  J. Stefan
Institute, 1000 Ljubljana, Slovenia  F. Pham  School of Physics, University of
Melbourne, Victoria 3010, Australia  M. Piccolo  INFN Laboratori Nazionali di
Frascati, I-00044 Frascati, Italy  L. E. Piilonen  Virginia Polytechnic
Institute and State University, Blacksburg, Virginia 24061, U.S.A.  G. Pinna
Angioni  Dipartimento di Fisica, Università di Torino, I-10125 Torino, Italy
INFN Sezione di Torino, I-10125 Torino, Italy  P. L. M. Podesta-Lerma
Universidad Autonoma de Sinaloa, Sinaloa 80000, Mexico  T. Podobnik  J. Stefan
Institute, 1000 Ljubljana, Slovenia  S. Pokharel  University of Mississippi,
University, Mississippi 38677, U.S.A.  L. Polat  Aix Marseille Université,
CNRS/IN2P3, CPPM, 13288 Marseille, France  V. Popov  National Research
University Higher School of Economics, Moscow 101000, Russian Federation  C.
Praz  Deutsches Elektronen–Synchrotron, 22607 Hamburg, Germany  S. Prell  Iowa
State University, Ames, Iowa 50011, U.S.A.  E. Prencipe  Justus-Liebig-
Universität Gießen, 35392 Gießen, Germany  M. T. Prim  University of Bonn,
53115 Bonn, Germany  M. V. Purohit  Okinawa Institute of Science and
Technology, Okinawa 904-0495, Japan  H. Purwar  University of Hawaii,
Honolulu, Hawaii 96822, U.S.A.  N. Rad  Deutsches Elektronen–Synchrotron,
22607 Hamburg, Germany  P. Rados  Institute of High Energy Physics, Vienna
1050, Austria  S. Raiz  Dipartimento di Fisica, Università di Trieste, I-34127
Trieste, Italy  INFN Sezione di Trieste, I-34127 Trieste, Italy  R. Rasheed
Université de Strasbourg, CNRS, IPHC, UMR 7178, 67037 Strasbourg, France  M.
Reif  Max-Planck-Institut für Physik, 80805 München, Germany  S. Reiter
Justus-Liebig-Universität Gießen, 35392 Gießen, Germany  M. Remnev  Budker
Institute of Nuclear Physics SB RAS, Novosibirsk 630090, Russian Federation
Novosibirsk State University, Novosibirsk 630090, Russian Federation  P. K.
Resmi  Indian Institute of Technology Madras, Chennai 600036, India  I. Ripp-
Baudot  Université de Strasbourg, CNRS, IPHC, UMR 7178, 67037 Strasbourg,
France  M. Ritter  Ludwig Maximilians University, 80539 Munich, Germany  M.
Ritzert  University of Heidelberg, 68131 Mannheim, Germany  G. Rizzo
Dipartimento di Fisica, Università di Pisa, I-56127 Pisa, Italy  INFN Sezione
di Pisa, I-56127 Pisa, Italy  L. B. Rizzuto  J. Stefan Institute, 1000
Ljubljana, Slovenia  S. H. Robertson  McGill University, Montréal, Québec, H3A
2T8, Canada  Institute of Particle Physics (Canada), Victoria, British
Columbia V8W 2Y2, Canada  D. Rodríguez Pérez  Universidad Autonoma de Sinaloa,
Sinaloa 80000, Mexico  J. M. Roney  University of Victoria, Victoria, British
Columbia, V8W 3P6, Canada  Institute of Particle Physics (Canada), Victoria,
British Columbia V8W 2Y2, Canada  C. Rosenfeld  University of South Carolina,
Columbia, South Carolina 29208, U.S.A.  A. Rostomyan  Deutsches
Elektronen–Synchrotron, 22607 Hamburg, Germany  N. Rout  Indian Institute of
Technology Madras, Chennai 600036, India  M. Rozanska  H. Niewodniczanski
Institute of Nuclear Physics, Krakow 31-342, Poland  G. Russo  Dipartimento di
Scienze Fisiche, Università di Napoli Federico II, I-80126 Napoli, Italy  INFN
Sezione di Napoli, I-80126 Napoli, Italy  D. Sahoo  Iowa State University,
Ames, Iowa 50011, U.S.A.  Y. Sakai  High Energy Accelerator Research
Organization (KEK), Tsukuba 305-0801, Japan  The Graduate University for
Advanced Studies (SOKENDAI), Hayama 240-0193, Japan  D. A. Sanders  University
of Mississippi, University, Mississippi 38677, U.S.A.  S. Sandilya  Indian
Institute of Technology Hyderabad, Telangana 502285, India  A. Sangal
University of Cincinnati, Cincinnati, Ohio 45221, U.S.A.  L. Santelj  Faculty
of Mathematics and Physics, University of Ljubljana, 1000 Ljubljana, Slovenia
J. Stefan Institute, 1000 Ljubljana, Slovenia  P. Sartori  Dipartimento di
Fisica e Astronomia, Università di Padova, I-35131 Padova, Italy  INFN Sezione
di Padova, I-35131 Padova, Italy  Y. Sato  High Energy Accelerator Research
Organization (KEK), Tsukuba 305-0801, Japan  V. Savinov  University of
Pittsburgh, Pittsburgh, Pennsylvania 15260, U.S.A.  B. Scavino  Institut für
Kernphysik, Johannes Gutenberg-Universität Mainz, D-55099 Mainz, Germany  M.
Schram  Pacific Northwest National Laboratory, Richland, Washington 99352,
U.S.A.  H. Schreeck  II. Physikalisches Institut, Georg-August-Universität
Göttingen, 37073 Göttingen, Germany  J. Schueler  University of Hawaii,
Honolulu, Hawaii 96822, U.S.A.  C. Schwanda  Institute of High Energy Physics,
Vienna 1050, Austria  A. J. Schwartz  University of Cincinnati, Cincinnati,
Ohio 45221, U.S.A.  B. Schwenker  II. Physikalisches Institut, Georg-August-
Universität Göttingen, 37073 Göttingen, Germany  Y. Seino  Niigata University,
Niigata 950-2181, Japan  A. Selce  INFN Sezione di Roma Tre, I-00146 Roma,
Italy  ENEA Casaccia, I-00123 Roma, Italy  K. Senyo  Yamagata University,
Yamagata 990-8560, Japan  I. S. Seong  University of Hawaii, Honolulu, Hawaii
96822, U.S.A.  J. Serrano  Aix Marseille Université, CNRS/IN2P3, CPPM, 13288
Marseille, France  M. E. Sevior  School of Physics, University of Melbourne,
Victoria 3010, Australia  C. Sfienti  Institut für Kernphysik, Johannes
Gutenberg-Universität Mainz, D-55099 Mainz, Germany  V. Shebalin  University
of Hawaii, Honolulu, Hawaii 96822, U.S.A.  C. P. Shen  Beihang University,
Beijing 100191, China  H. Shibuya  Toho University, Funabashi 274-8510, Japan
T. Shillington  McGill University, Montréal, Québec, H3A 2T8, Canada  J.-G.
Shiu  Department of Physics, National Taiwan University, Taipei 10617, Taiwan
B. Shwartz  Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090,
Russian Federation  Novosibirsk State University, Novosibirsk 630090, Russian
Federation  A. Sibidanov  University of Hawaii, Honolulu, Hawaii 96822, U.S.A.
F. Simon  Max-Planck-Institut für Physik, 80805 München, Germany  J. B. Singh
Panjab University, Chandigarh 160014, India  S. Skambraks  Institut für
Experimentelle Teilchenphysik, Karlsruher Institut für Technologie, 76131
Karlsruhe, Germany  K. Smith  School of Physics, University of Melbourne,
Victoria 3010, Australia  R. J. Sobie  University of Victoria, Victoria,
British Columbia, V8W 3P6, Canada  Institute of Particle Physics (Canada),
Victoria, British Columbia V8W 2Y2, Canada  A. Soffer  Tel Aviv University,
School of Physics and Astronomy, Tel Aviv, 69978, Israel  A. Sokolov
Institute for High Energy Physics, Protvino 142281, Russian Federation  Y.
Soloviev  Deutsches Elektronen–Synchrotron, 22607 Hamburg, Germany  E.
Solovieva  P.N. Lebedev Physical Institute of the Russian Academy of Sciences,
Moscow 119991, Russian Federation  S. Spataro  Dipartimento di Fisica,
Università di Torino, I-10125 Torino, Italy  INFN Sezione di Torino, I-10125
Torino, Italy  B. Spruck  Institut für Kernphysik, Johannes Gutenberg-
Universität Mainz, D-55099 Mainz, Germany  M. Starič  J. Stefan Institute,
1000 Ljubljana, Slovenia  S. Stefkova  Deutsches Elektronen–Synchrotron, 22607
Hamburg, Germany  Z. S. Stottler  Virginia Polytechnic Institute and State
University, Blacksburg, Virginia 24061, U.S.A.  R. Stroili  Dipartimento di
Fisica e Astronomia, Università di Padova, I-35131 Padova, Italy  INFN Sezione
di Padova, I-35131 Padova, Italy  J. Strube  Pacific Northwest National
Laboratory, Richland, Washington 99352, U.S.A.  J. Stypula  H. Niewodniczanski
Institute of Nuclear Physics, Krakow 31-342, Poland  R. Sugiura  Department of
Physics, University of Tokyo, Tokyo 113-0033, Japan  M. Sumihama  Gifu
University, Gifu 501-1193, Japan  Research Center for Nuclear Physics, Osaka
University, Osaka 567-0047, Japan  K. Sumisawa  High Energy Accelerator
Research Organization (KEK), Tsukuba 305-0801, Japan  The Graduate University
for Advanced Studies (SOKENDAI), Hayama 240-0193, Japan  T. Sumiyoshi  Tokyo
Metropolitan University, Tokyo 192-0397, Japan  D. J. Summers  University of
Mississippi, University, Mississippi 38677, U.S.A.  W. Sutcliffe  University
of Bonn, 53115 Bonn, Germany  S. Y. Suzuki  High Energy Accelerator Research
Organization (KEK), Tsukuba 305-0801, Japan  The Graduate University for
Advanced Studies (SOKENDAI), Hayama 240-0193, Japan  H. Svidras  Deutsches
Elektronen–Synchrotron, 22607 Hamburg, Germany  M. Tabata  Chiba University,
Chiba 263-8522, Japan  M. Takahashi  Deutsches Elektronen–Synchrotron, 22607
Hamburg, Germany  M. Takizawa  Meson Science Laboratory, Cluster for
Pioneering Research, RIKEN, Saitama 351-0198, Japan  J-PARC Branch, KEK Theory
Center, High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801,
Japan  Showa Pharmaceutical University, Tokyo 194-8543, Japan  U. Tamponi
INFN Sezione di Torino, I-10125 Torino, Italy  S. Tanaka  High Energy
Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan  The Graduate
University for Advanced Studies (SOKENDAI), Hayama 240-0193, Japan  K. Tanida
Advanced Science Research Center, Japan Atomic Energy Agency, Naka 319-1195,
Japan  H. Tanigawa  Department of Physics, University of Tokyo, Tokyo
113-0033, Japan  N. Taniguchi  High Energy Accelerator Research Organization
(KEK), Tsukuba 305-0801, Japan  Y. Tao  University of Florida, Gainesville,
Florida 32611, U.S.A.  P. Taras  Université de Montréal, Physique des
Particules, Montréal, Québec, H3C 3J7, Canada  F. Tenchini  Dipartimento di
Fisica, Università di Pisa, I-56127 Pisa, Italy  INFN Sezione di Pisa, I-56127
Pisa, Italy  R. Tiwary  Tata Institute of Fundamental Research, Mumbai 400005,
India  D. Tonelli  INFN Sezione di Trieste, I-34127 Trieste, Italy  E. Torassa
INFN Sezione di Padova, I-35131 Padova, Italy  N. Toutounji  School of
Physics, University of Sydney, New South Wales 2006, Australia  K. Trabelsi
Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405 Orsay, France  T. Tsuboyama
High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan
The Graduate University for Advanced Studies (SOKENDAI), Hayama 240-0193,
Japan  N. Tsuzuki  Graduate School of Science, Nagoya University, Nagoya
464-8602, Japan  M. Uchida  Tokyo Institute of Technology, Tokyo 152-8550,
Japan  I. Ueda  High Energy Accelerator Research Organization (KEK), Tsukuba
305-0801, Japan  The Graduate University for Advanced Studies (SOKENDAI),
Hayama 240-0193, Japan  S. Uehara  High Energy Accelerator Research
Organization (KEK), Tsukuba 305-0801, Japan  The Graduate University for
Advanced Studies (SOKENDAI), Hayama 240-0193, Japan  Y. Uematsu  Department of
Physics, University of Tokyo, Tokyo 113-0033, Japan  T. Ueno  Department of
Physics, Tohoku University, Sendai 980-8578, Japan  T. Uglov  P.N. Lebedev
Physical Institute of the Russian Academy of Sciences, Moscow 119991, Russian
Federation  National Research University Higher School of Economics, Moscow
101000, Russian Federation  K. Unger  Institut für Experimentelle
Teilchenphysik, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany
Y. Unno  Department of Physics and Institute of Natural Sciences, Hanyang
University, Seoul 04763, South Korea  K. Uno  Niigata University, Niigata
950-2181, Japan  S. Uno  High Energy Accelerator Research Organization (KEK),
Tsukuba 305-0801, Japan  The Graduate University for Advanced Studies
(SOKENDAI), Hayama 240-0193, Japan  P. Urquijo  School of Physics, University
of Melbourne, Victoria 3010, Australia  Y. Ushiroda  High Energy Accelerator
Research Organization (KEK), Tsukuba 305-0801, Japan  The Graduate University
for Advanced Studies (SOKENDAI), Hayama 240-0193, Japan  Department of
Physics, University of Tokyo, Tokyo 113-0033, Japan  Y. V. Usov  Budker
Institute of Nuclear Physics SB RAS, Novosibirsk 630090, Russian Federation
Novosibirsk State University, Novosibirsk 630090, Russian Federation  S. E.
Vahsen  University of Hawaii, Honolulu, Hawaii 96822, U.S.A.  R. van Tonder
University of Bonn, 53115 Bonn, Germany  G. S. Varner  University of Hawaii,
Honolulu, Hawaii 96822, U.S.A.  K. E. Varvell  School of Physics, University
of Sydney, New South Wales 2006, Australia  A. Vinokurova  Budker Institute of
Nuclear Physics SB RAS, Novosibirsk 630090, Russian Federation  Novosibirsk
State University, Novosibirsk 630090, Russian Federation  L. Vitale
Dipartimento di Fisica, Università di Trieste, I-34127 Trieste, Italy  INFN
Sezione di Trieste, I-34127 Trieste, Italy  V. Vorobyev  Budker Institute of
Nuclear Physics SB RAS, Novosibirsk 630090, Russian Federation  P.N. Lebedev
Physical Institute of the Russian Academy of Sciences, Moscow 119991, Russian
Federation  Novosibirsk State University, Novosibirsk 630090, Russian
Federation  A. Vossen  Duke University, Durham, North Carolina 27708, U.S.A.
B. Wach  Max-Planck-Institut für Physik, 80805 München, Germany  E. Waheed
High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan
H. M. Wakeling  McGill University, Montréal, Québec, H3A 2T8, Canada  K. Wan
Department of Physics, University of Tokyo, Tokyo 113-0033, Japan  W. Wan
Abdullah  National Centre for Particle Physics, University Malaya, 50603 Kuala
Lumpur, Malaysia  B. Wang  Max-Planck-Institut für Physik, 80805 München,
Germany  C. H. Wang  National United University, Miao Li 36003, Taiwan  E.
Wang  University of Pittsburgh, Pittsburgh, Pennsylvania 15260, U.S.A.  M.-Z.
Wang  Department of Physics, National Taiwan University, Taipei 10617, Taiwan
X. L. Wang  Key Laboratory of Nuclear Physics and Ion-beam Application (MOE)
and Institute of Modern Physics, Fudan University, Shanghai 200443, China  A.
Warburton  McGill University, Montréal, Québec, H3A 2T8, Canada  M. Watanabe
Niigata University, Niigata 950-2181, Japan  S. Watanuki  Yonsei University,
Seoul 03722, South Korea  J. Webb  School of Physics, University of Melbourne,
Victoria 3010, Australia  S. Wehle  Deutsches Elektronen–Synchrotron, 22607
Hamburg, Germany  M. Welsch  University of Bonn, 53115 Bonn, Germany  C.
Wessel  University of Bonn, 53115 Bonn, Germany  J. Wiechczynski  H.
Niewodniczanski Institute of Nuclear Physics, Krakow 31-342, Poland  P.
Wieduwilt  II. Physikalisches Institut, Georg-August-Universität Göttingen,
37073 Göttingen, Germany  H. Windel  Max-Planck-Institut für Physik, 80805
München, Germany  E. Won  Korea University, Seoul 02841, South Korea  L. J. Wu
Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049,
China  X. P. Xu  Soochow University, Suzhou 215006, China  B. D. Yabsley
School of Physics, University of Sydney, New South Wales 2006, Australia  S.
Yamada  High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801,
Japan  W. Yan  University of Science and Technology of China, Hefei 230026,
China  S. B. Yang  Korea University, Seoul 02841, South Korea  H. Ye
Deutsches Elektronen–Synchrotron, 22607 Hamburg, Germany  J. Yelton
University of Florida, Gainesville, Florida 32611, U.S.A.  I. Yeo  Korea
Institute of Science and Technology Information, Daejeon 34141, South Korea
J. H. Yin  Korea University, Seoul 02841, South Korea  M. Yonenaga  Tokyo
Metropolitan University, Tokyo 192-0397, Japan  Y. M. Yook  Institute of High
Energy Physics, Chinese Academy of Sciences, Beijing 100049, China  K.
Yoshihara  Graduate School of Science, Nagoya University, Nagoya 464-8602,
Japan  T. Yoshinobu  Niigata University, Niigata 950-2181, Japan  C. Z. Yuan
Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049,
China  G. Yuan  University of Science and Technology of China, Hefei 230026,
China  Y. Yusa  Niigata University, Niigata 950-2181, Japan  L. Zani  Aix
Marseille Université, CNRS/IN2P3, CPPM, 13288 Marseille, France  Y. Zhai  Iowa
State University, Ames, Iowa 50011, U.S.A.  J. Z. Zhang  Institute of High
Energy Physics, Chinese Academy of Sciences, Beijing 100049, China  Y. Zhang
University of Science and Technology of China, Hefei 230026, China  Y. Zhang
Key Laboratory of Nuclear Physics and Ion-beam Application (MOE) and Institute
of Modern Physics, Fudan University, Shanghai 200443, China  Z. Zhang
University of Science and Technology of China, Hefei 230026, China  V. Zhilich
Budker Institute of Nuclear Physics SB RAS, Novosibirsk 630090, Russian
Federation  Novosibirsk State University, Novosibirsk 630090, Russian
Federation  J. Zhou  Key Laboratory of Nuclear Physics and Ion-beam
Application (MOE) and Institute of Modern Physics, Fudan University, Shanghai
200443, China  Q. D. Zhou  Graduate School of Science, Nagoya University,
Nagoya 464-8602, Japan  Institute for Advanced Research, Nagoya University,
Nagoya 464-8602, Japan  Kobayashi-Maskawa Institute, Nagoya University, Nagoya
464-8602, Japan  X. Y. Zhou  Liaoning Normal University, Dalian 116029, China
V. I. Zhukova  P.N. Lebedev Physical Institute of the Russian Academy of
Sciences, Moscow 119991, Russian Federation  V. Zhulanov  Budker Institute of
Nuclear Physics SB RAS, Novosibirsk 630090, Russian Federation  Novosibirsk
State University, Novosibirsk 630090, Russian Federation

###### Abstract

We report a measurement of the branching fraction of inclusive semileptonic
$B$ meson decays $B\rightarrow X_{c}\ell\nu_{\ell}$ in $\mathchar
28935\relax(4S)\rightarrow B\bar{B}$ data recorded by the Belle II experiment
at the SuperKEKB asymmetric-energy $e^{+}e^{-}$ collider and corresponding to
$62.8\text{\,}{\mathrm{fb}}^{-1}$ of integrated luminosity. Only a charged
lepton (electon or muon) is reconstructed and the signal yield is determined
from a fit to the lepton momentum distribution in the center-of-mass frame of
the colliding beams. Averaging the result in the electron and muon channels,
we find ${\cal B}(B\rightarrow X_{c}\ell\nu_{\ell})=(9.75\pm
0.03(\text{stat})\pm 0.47(\text{sys}))\%$.

##  1 Introduction

The magnitude of the Cabibbo-Kobayashi-Maskawa (CKM) [1, 2] matrix element
$|V_{cb}|$ squared determines the transition rate of $b$ into $c$ quarks. The
precise knowledge of this fundamental parameter of the Standard Model (SM) [3]
is crucial for the ongoing precision $B$ physics programme at the Belle II
experiment and elsewhere. The CKM element $|V_{cb}|$ is measured from
semileptonic $B$ meson decays $B\rightarrow X_{c}\ell\nu_{\ell}$, where
$X_{c}$ is a hadronic system with charm, $\ell$ is a light charged lepton
(electron or muon) and $\nu$ is the associated neutrino. These determinations
can be inclusive, i.e., sensitive to all $X_{c}\ell\nu_{\ell}$ final states
within a given region of phase space, or exclusive, i.e., based only on a
single $b\rightarrow c$ semileptonic mode such as $B\rightarrow D^{*}\ell\nu$
or $B\rightarrow D\ell\nu$. Pursuing both approaches is important as the two
avenues involve different theoretical and experimental uncertainties and
consistency between both is a powerful consistency check of our understanding.
However, inclusive and exclusive measurements of $|V_{cb}|$ have been at odds
for many years now, an issue which is often referred to as the _inclusive vs.
exclusive problem_ [4].

In this paper we describe a measurement of the inclusive semileptonic
branching ratio based on the Belle II data collected in the years 2019 and
2020 equivalent to $62.8\text{\,}{\mathrm{fb}}^{-1}$. The paper is organized
as follows: Sect. 2 describes the collision data and simulated data samples
used in this analysis. Sect. 3 introduces our experimental procedure. Finally,
Sect. 4 contains all results and the analysis of systematic uncertainties.

##  2 The Belle II detector and data sample

The Belle II detector [5] operates at the SuperKEKB asymmetric-energy
electron-positron collider [6], located at the KEK laboratory in Tsukuba,
Japan. The detector consists of several nested detector subsystems arranged
around the beam pipe in a cylindrical geometry. The innermost subsystem is the
vertex detector, which includes two layers of silicon pixel detectors and four
outer layers of silicon strip detectors. Currently, the second pixel layer is
installed in only a small part of the solid angle, while the remaining vertex
detector layers are fully installed. Most of the tracking volume consists of a
helium and ethane-based small-cell drift chamber (CDC). Outside the drift
chamber, a Cherenkov-light imaging and time-of-propagation detector provides
charged-particle identification in the barrel region. In the forward endcap,
this function is provided by a proximity-focusing, ring-imaging Cherenkov
detector with an aerogel radiator. Further out is the ECL electromagnetic
calorimeter, consisting of a barrel and two endcap sections made of CsI(Tl)
crystals. A uniform 1.5 T magnetic field is provided by a superconducting
solenoid situated outside the calorimeter. Multiple layers of scintillators
and resistive plate chambers, located between the magnetic flux-return iron
plates, constitute the $K_{L}$ and muon identification system (KLM).

The data used in this analysis were collected between March 2019 and July 2020
and correspond to $62.8\text{\,}{\mathrm{fb}}^{-1}$ of integrated luminosity
on the $\mathchar 28935\relax(4S)$ resonance (10.58 GeV) and
$9.2\text{\,}{\mathrm{fb}}^{-1}$ of integrated luminosity below the $\mathchar
28935\relax(4S)$ resonance (10.52 GeV), referred to as off-resonance data.
Collected data sample contains $N_{B\bar{B}}=\left(68.21\pm
0.06(\text{stat})\pm 0.75(\text{sys})\right)\times 10^{6}$ $\mathchar
28935\relax(4S)\rightarrow B\bar{B}$ events as determined from a fit to event-
shape variables [7]. In addition, we use Monte Carlo (MC) simulated events
equivalent to $200\text{\,}{\mathrm{fb}}^{-1}$ throughout this analysis. These
include a sample of $\mathchar 28935\relax(4S)\rightarrow B\bar{B}$ events in
which $B$ mesons decay generically, generated with EvtGen [8] and a sample of
continuum $e^{+}e^{-}\rightarrow q\bar{q}$ events ($q=u,d,s,c$) simulated with
KKMC [9], interfaced with PYTHIA [10]. The $B\bar{B}$ sample includes
semileptonic $B$ meson decays $B\rightarrow X\ell\nu$, where $X$ can be a
hadronic system with and without charm. The latter is modeled by a mixture of
exclusive modes ($X_{u}$ can either be charged or neutral $\pi$, $\rho$,
$\omega$ or $\eta$) and an inclusive model [11]. Full detector simulation
based on GEANT4 [12] is applied to MC events. The lepton reconstruction
efficiencies and the hadron misidentification rates in simulation are adjusted
to match the real performance of the Belle II lepton identification system.

Both data and simulated events are analysed with Belle II analysis software
framework (BASF2) [13]. Hadronic events are selected and backgrounds coming
from quantum electrodynamic processes (low multiplicity events) are reduced by
requiring more than three charged tracks in a single event, the total energy
of the reconstructed charged and neutral particles above 4 GeV and a ratio
$R_{2}$ of the second to the zeroth Fox-Wolfram moment below 0.4 [14].

##  3 Experimental Procedure

###  3.1 Reconstruction

We require charged particle tracks to originate from the interaction point
(IP): The distance of closest approach between each track and the interaction
point is required to be less than 2 cm along the $z$ direction (parallel to
the beams) and less than 0.5 cm in the transverse $r-\phi$ plane. We further
require charged particles to be within acceptance of the central drift chamber
(CDC) and to have transverse momentum above 100
${\mathrm{\,Me\kern-1.00006ptV\\!/}c}$.

In the next step, we identify charged lepton candidates (electrons or muons).
The particle’s center-of-mass (c.m.) momentum $p_{\ell}^{*}$ must lie in the
range between 0.4 and 2.5 ${\mathrm{\,Ge\kern-1.00006ptV\\!/}c}$. Electrons
are identified based on their energy and shower shape in the ECL calorimeter.
Muons are identified using information from the instrumented return yoke KLM.
We require the lepton candidates to have momenta in the laboratory frame
within the range of $p_{\ell}\in[0.4,2.5]$
${\mathrm{\,Ge\kern-1.00006ptV\\!/}c}$ and polar angle
$\theta_{e}\in[0.22,2.71]$ rad for electrons and $\theta_{\mu}\in[0.4,2.6]$
rad for muons. We veto charged leptons from $J/\psi$ decays or from photon
conversion. Each lepton candidate is combined with an oppositely charged
particle and two regions of invariant mass $M(\ell^{+}\ell^{-})$ are excluded
– the interval $[3.0,3.14]$ ${\mathrm{\,Ge\kern-1.00006ptV\\!/}c^{2}}$ for
electrons and $[3.04,3.14]$ ${\mathrm{\,Ge\kern-1.00006ptV\\!/}c^{2}}$ for
muons. Photon conversions to an electron pair are vetoed by rejecting electron
positron pairs with an invariant mass below 0.14 GeV. We also reject events
with more than one lepton candidate.

We exclude events where the missing momentum is not consistent with the
presence of a single neutrino from the semileptonic $B$ decay. In particular
we impose the event-level selections on the following three properties:
missing mass (magnitude of the missing four-momentum) is required to be
$M_{miss}^{2}<$ 3 GeV2, the polar angle of the missing three-momentum has to
lie within $\theta_{miss}\in[0.3,2.6]$ rad and the absolute value of the total
event charge is restricted to $|\sum_{i}q_{i}|<3$.

The MC samples are scaled to the data luminosity and split up into the
following components: $B\rightarrow X_{c}\ell\nu_{\ell}$ signal, $B\rightarrow
X_{u}\ell\nu_{\ell}$ background, the events where the lepton candidate is
misidentified (referred to as fakes or fake leptons), $b\rightarrow
c/\bar{c}\rightarrow\ell$ (secondary leptons), and other $B\bar{B}$ background
(the lepton candidate does not belong in any of these categories). The lepton
identification at Belle II is described in [15].

###  3.2 Signal extraction

We extract the amount of $B\rightarrow X_{c}\ell\nu_{\ell}$ signal and
background by performing a fit to the binned c.m. lepton momentum
distribution, separately in the electron and in the muon samples. We use a
maximum likelihood technique using Poisson statistics of both real and MC
simulated data [16]. The following components are freely floated in this fit:
the $b\rightarrow c$ signal, $B\bar{B}$ backgrounds (including $b\rightarrow
u$, fake and secondary leptons and other $B\bar{B}$ backgrounds) and the
continuum background. The shape in $p^{*}_{\ell}$ of the signal and $B\bar{B}$
backgrounds components are obtained from MC simulation, while the shape of the
continuum background is modeled by off-resonance collision data equivalent to
$9.2\text{\,}{\mathrm{fb}}^{-1}$, taken at the c.m. energy of
$10.52\text{\,}\mathrm{GeV}$.

It is necessary to combine all $B\bar{B}$ background contributions into a
single fit component because they have similar shapes in $p^{*}_{\ell}$ and
the fit would otherwise have difficulties to distinguish them. However, we
vary the relative amounts of these background components when evaluating the
systematic uncertainty related to the background and repeat the fit with
altered compositions of the background.

Fig. 1 shows the c.m. frame electron and muon momentum distributions after the
fit. Table 1 gives the yields of the various components and their respective
uncertainties determined by the fit.

Figure 1: C.m. frame electron (left) and muon (right) momentum distributions
after the fit. See text for more details.

Table 1: Yields in the electron and muon samples. Note that the $b\rightarrow u$, fake and secondary leptons and other $B\bar{B}$ background components are combined in a single fit component and that they are split up here for better understanding. See text for more details. Yield | Electron mode | Muon mode
---|---|---
Signal | $(1.932\pm 0.006)\times 10^{6}$ | $(1.501\pm 0.007)\times 10^{6}$
$b\rightarrow u$ background | $(53.4\pm 0.4)\times 10^{3}$ | $(52\pm 1)\times 10^{3}$
Fake leptons | $(1.258\pm 0.009)\times 10^{6}$ | $(3.15\pm 0.07)\times 10^{6}$
Secondaries | $(1.324\pm 0.009)\times 10^{6}$ | $(0.89\pm 0.02)\times 10^{6}$
Other $B\bar{B}$ background | $(5.42\pm 0.04)\times 10^{3}$ | $(4.33\pm 0.09)\times 10^{3}$
Continuum | $(5.51\pm 0.02)\times 10^{6}$ | $(7.35\pm 0.09)\times 10^{6}$
Sum | $(10.08\pm 0.03)\times 10^{6}$ | $(13.0\pm 0.1)\times 10^{6}$

##  4 Results and systematic uncertainties

###  4.1 Inclusive semileptonic branching fraction

In this section we determine the inclusive branching fraction of semileptonic
decays $B\rightarrow X_{c}\ell\nu_{\ell}$ where $B$ is a state with the
average lifetime of $B^{+}$ and $B^{0}$,
$\tau=(\tau(B^{+})+\tau(B^{0}))/2=(1.579\pm 0.004)$ ps [17]. As spectator
effects in semileptonic decays are known to be small [18, 19], we assume a
common semileptonic width

$\Gamma_{\mathrm{s.l.}}=\frac{{\cal B}(B^{+}\rightarrow
X_{c}\ell\nu_{\ell})}{\tau(B^{+})}=\frac{{\cal B}(B^{0}\rightarrow
X_{c}\ell\nu_{\ell})}{\tau(B^{0})}=\frac{{\cal B}(B\rightarrow
X_{c}\ell\nu_{\ell})}{\tau}~{},$ (1)

and calculate the inclusive semileptonic branching fraction as

${\cal B}(B\rightarrow
X_{c}\ell\nu_{\ell})=\frac{N^{\ell}_{\mathrm{sig}}\tau}{2N_{B\bar{B}}\Big{(}f_{+}\epsilon^{\ell}(B^{+})\tau(B^{+})+f_{0}\epsilon^{\ell}(B^{0})\tau(B^{0})\Big{)}},$
(2)

where $N^{\ell}_{\mathrm{sig}}$ is the fitted number of signal events in the
respective sample, $N_{B\bar{B}}$ is the total number of $B\bar{B}$ pairs in
the data sample and $\epsilon^{\ell}(B)$ is the signal selection efficiency in
the respective sample. The factor of two accounts for the fact that both $B$
mesons in the $\mathchar 28935\relax(4S)$ event can contribute to the signal.
The factors $\tau(B^{+}/B^{0})$ are the mean lifetimes of the mesons and the
$f_{+/0}$ are the production fractions of the two $B$ species at the
$\mathchar 28935\relax(4S)$. We determine them from $f_{+}/f_{0}=1.058\pm
0.024$ [17] to be $f_{+}=0.514\pm 0.006$ and $f_{0}=0.486\pm 0.006$.

The signal selection efficiencies were determined from MC simulation for the
$B^{+}$ and $B^{0}$ events separately. The electron mode efficiencies after
all applied selections are $\epsilon^{e}(B^{+})=15.76\%$ and
$\epsilon^{e}(B^{0})=12.40\%$. The muon mode has somewhat lower signal
selection efficiencies of $\epsilon^{\mu}(B^{+})=12.99\%$ and
$\epsilon^{\mu}(B^{0})=10.03\%$.

From this equation we obtain the following branching fractions in the electron
and muon samples. The uncertainty is statistical only, i.e., corresponds to
the uncertainty in the fitted signal fraction.

$\displaystyle{\cal B}(B\rightarrow X_{c}e\nu_{e})$ $\displaystyle=$
$\displaystyle(9.97\pm 0.03(\text{stat}))\%~{},$ (3) $\displaystyle{\cal
B}(B\rightarrow X_{c}\mu\nu_{\mu})$ $\displaystyle=$ $\displaystyle(9.47\pm
0.05(\text{stat}))\%~{}.$ (4)

###  4.2 Systematic Uncertainties

The main contribution is model uncertainty in the $B\rightarrow
X_{c}\ell\nu_{\ell}$ signal and in the $B\bar{B}$ background component. The
$B\rightarrow X_{c}\ell\nu_{\ell}$ modelling uncertainty in Monte Carlo was
determined in the following way: At first, the inclusive signal sample was
split into 30 separate decay modes. The branching fraction of the mode under
consideration was varied by $\pm 1\sigma$ of the current average branching
fraction, taken from the Particle Data Group [17]. The whole sample was then
fitted again and the number of signal events was obtained from the fit. The
systematic uncertainty was calculated for each decay mode from the difference
between maximal and minimal yield, and the true signal yield from Table 1. The
full modeling uncertainty is calculated by adding the separate contributions
in quadrature.

The decay form factors affect the shape of the Monte Carlo template in center-
of-mass (c.m.) momentum $p_{\ell}^{*}$. The form factor uncertainty is
estimated by assuming the Caprini, Lellouch and Neubert (CLN) parameterization
[20] for the $B\rightarrow D^{*}\ell\nu_{\ell}$ and $B\rightarrow
D\ell\nu_{\ell}$ decays and varying the form factor parameters within their
ranges of uncertainty [4].

To estimate the uncertainty in the $B\bar{B}$ background, we vary all four
contributions ($b\rightarrow u$, secondary leptons, fake leptons and others)
by 5%, which roughly corresponds to the difference between pre-fit and post-
fit yields of the background. We determine uncertainties in the same way as
for the $B\rightarrow X_{c}\ell\nu_{\ell}$ model. Furthermore, we constrain
continuum background to the ratio between on- and off-resonance data of
$62.8\text{\,}{\mathrm{fb}}^{-1}$/$9.2\text{\,}{\mathrm{fb}}^{-1}$, allowing
it to float only within the uncertainty of the luminosity measurement (later
referred to as ‘fixed’ continuum ratio). The uncertainty assigned to the
continuum background is the difference between yields with ‘fixed’ and fully
floating fraction in the fit. Details on the determination of the background
model uncertainty are collected in Table 2.

Table 2: Determination of the background model uncertainty. The table shows the change in fitted signal yield when varying individual background components by $\pm 5\%$. | Electron mode | Muon mode
---|---|---
Varying background | $N_{sig,0.95}$ | $N_{sig,1.05}$ |  $\sigma_{rel}$ [%] | $N_{sig,0.95}$ | $N_{sig,1.05}$ |  $\sigma_{rel}$ [%]
$b\rightarrow u$ | 1934639 | 1928820 | 0.15 | 1505782 | 1509395 | 0.12
Fake leptons | 1930435 | 1928590 | 0.05 | 1519457 | 1511576 | 0.26
Secondaries | 1927430 | 1934593 | 0.19 | 1506999 | 1508290 | 0.04
Others | 1932781 | 1932126 | 0.02 | 1508798 | 1503859 | 0.16
Continuum data (‘fixed’ ratio) | 1925908 | 0.34 | 1457793 | 2.91

Other components are uncertainties related to tracking, to the counting of
$B\bar{B}$ events and to lepton identification. The uncertainty related to
lepton identification is estimated by generating 200 variations of the
simulated events with lepton identification efficiency and misidentification
rates chosen randomly within their respective uncertainties. For each
variation, the number of signal events ($N_{sig,i}$) is calculated. The mean
value and the standard deviation of the distribution of the obtained yields
$N_{sig,i}$ are used to determine the lepton identification uncertainty.

A tracking uncertainty of 0.69% is applied to the only charged particle that
is reconstructed. The uncertainty from limited MC sample size in the
reconstruction efficiency $\epsilon^{\ell}(B)$ is at the sub-permille level
and therefore negligible. Table 3 summarizes our estimate of the systematic
uncertainty in the electron and muon samples. The different components of
systematic uncertainty are added in quadrature and the overall relative
systematic uncertainties are found to be 3.77% and 4.79% for the electron and
muon modes, respectively.

Table 3: Estimated relative systematic uncertainty on the $B\rightarrow X_{c}\ell\nu_{\ell}$ branching fraction measurement in the two modes. | Relative uncertainty [%]
---|---
Contribution | Electron mode | Muon mode
Tracking | 0.69 | 0.69
$N_{B\bar{B}}$ | 1.1 | 1.1
Lepton ID corrections | 1.64 | 2.33
$f_{0}/f_{+}$, $B$ lifetime | 1.2 | 1.2
$B\rightarrow X_{c}\ell\nu_{\ell}$ branching fractions | 2.65 | 2.15
$B\rightarrow X_{c}\ell\nu_{\ell}$ form factors | 1.11 | 1.11
$B\bar{B}$ background model | 0.24 | 0.34
Off-resonance data model | 0.34 | 2.91
Sum | 3.77 | 4.79

##  5 Conclusion

We have measured the inclusive $B\rightarrow X_{c}\ell\nu_{\ell}$ branching
ratio in a Belle II sample corresponding to $62.8\text{\,}{\mathrm{fb}}^{-1}$
of integrated luminosity. The preliminary results for both lepton modes are

$\displaystyle{\cal B}(B\rightarrow X_{c}e\nu_{e})$ $\displaystyle=$
$\displaystyle(9.97\pm 0.03(\text{stat})\pm 0.38(\text{sys}))\%~{},$ (5)
$\displaystyle{\cal B}(B\rightarrow X_{c}\mu\nu_{\mu})$ $\displaystyle=$
$\displaystyle(9.47\pm 0.05(\text{stat})\pm 0.45(\text{sys}))\%~{}.$ (6)

The combined branching fraction is determined as the weighted mean. We
conservatively assume electron and muon systematic uncertainties to be fully
correlated and use the (larger) muon systematic uncertainty for the combined
result. The average semileptonic branching fraction $B\rightarrow
X_{c}\ell\nu_{\ell}$ (where $\ell$ can be either an electron or a muon) is
thus found to be

${\cal B}(B\rightarrow X_{c}\ell\nu_{\ell})=(9.75\pm 0.03(\text{stat})\pm
0.47(\text{sys}))\%.$ (7)

##  6 Acknowledgments

We thank the SuperKEKB group for the excellent operation of the accelerator;
the KEK cryogenics group for the efficient operation of the solenoid; the KEK
computer group for on-site computing support; and the raw-data centers at BNL,
DESY, GridKa, IN2P3, and INFN for off-site computing support. This work was
supported by the following funding sources: Science Committee of the Republic
of Armenia Grant No. 20TTCG-1C010; Australian Research Council and research
grant Nos. DP180102629, DP170102389, DP170102204, DP150103061, FT130100303,
FT130100018, and FT120100745; Austrian Federal Ministry of Education, Science
and Research, Austrian Science Fund No. P 31361-N36, and Horizon 2020 ERC
Starting Grant no. 947006 “InterLeptons”; Natural Sciences and Engineering
Research Council of Canada, Compute Canada and CANARIE; Chinese Academy of
Sciences and research grant No. QYZDJ-SSW-SLH011, National Natural Science
Foundation of China and research grant Nos. 11521505, 11575017, 11675166,
11761141009, 11705209, and 11975076, LiaoNing Revitalization Talents Program
under contract No. XLYC1807135, Shanghai Municipal Science and Technology
Committee under contract No. 19ZR1403000, Shanghai Pujiang Program under Grant
No. 18PJ1401000, and the CAS Center for Excellence in Particle Physics
(CCEPP); the Ministry of Education, Youth and Sports of the Czech Republic
under Contract No. LTT17020 and Charles University grants SVV 260448 and GAUK
404316; European Research Council, 7th Framework PIEF-GA-2013-622527, Horizon
2020 ERC-Advanced Grants No. 267104 and 884719, Horizon 2020 ERC-Consolidator
Grant No. 819127, Horizon 2020 Marie Sklodowska-Curie grant agreement No.
700525 ‘NIOBE,’ and Horizon 2020 Marie Sklodowska-Curie RISE project JENNIFER2
grant agreement No. 822070 (European grants); L’Institut National de Physique
Nucléaire et de Physique des Particules (IN2P3) du CNRS (France); BMBF, DFG,
HGF, MPG, and AvH Foundation (Germany); Department of Atomic Energy under
Project Identification No. RTI 4002 and Department of Science and Technology
(India); Israel Science Foundation grant No. 2476/17, United States-Israel
Binational Science Foundation grant No. 2016113, and Israel Ministry of
Science grant No. 3-16543; Istituto Nazionale di Fisica Nucleare and the
research grants BELLE2; Japan Society for the Promotion of Science, Grant-in-
Aid for Scientific Research grant Nos. 16H03968, 16H03993, 16H06492, 16K05323,
17H01133, 17H05405, 18K03621, 18H03710, 18H05226, 19H00682, 26220706, and
26400255, the National Institute of Informatics, and Science Information
NETwork 5 (SINET5), and the Ministry of Education, Culture, Sports, Science,
and Technology (MEXT) of Japan; National Research Foundation (NRF) of Korea
Grant Nos. 2016R1D1A1B01010135, 2016R1D1A1B02012900, 2018R1A2B3003643,
2018R1A6A1A06024970, 2018R1D1A1B07047294, 2019K1A3A7A09033840, and
2019R1I1A3A01058933, Radiation Science Research Institute, Foreign Large-size
Research Facility Application Supporting project, the Global Science
Experimental Data Hub Center of the Korea Institute of Science and Technology
Information and KREONET/GLORIAD; Universiti Malaya RU grant, Akademi Sains
Malaysia and Ministry of Education Malaysia; Frontiers of Science Program
contracts FOINS-296, CB-221329, CB-236394, CB-254409, and CB-180023, and SEP-
CINVESTAV research grant 237 (Mexico); the Polish Ministry of Science and
Higher Education and the National Science Center; the Ministry of Science and
Higher Education of the Russian Federation, Agreement 14.W03.31.0026, and the
HSE University Basic Research Program, Moscow; University of Tabuk research
grants S-0256-1438 and S-0280-1439 (Saudi Arabia); Slovenian Research Agency
and research grant Nos. J1-9124 and P1-0135; Agencia Estatal de Investigacion,
Spain grant Nos. FPA2014-55613-P and FPA2017-84445-P, and CIDEGENT/2018/020 of
Generalitat Valenciana; Ministry of Science and Technology and research grant
Nos. MOST106-2112-M-002-005-MY3 and MOST107-2119-M-002-035-MY3, and the
Ministry of Education (Taiwan); Thailand Center of Excellence in Physics;
TUBITAK ULAKBIM (Turkey); National Research Foundation of Ukraine, project No.
2020.02/0257, and Ministry of Education and Science of Ukraine; the US
National Science Foundation and research grant Nos. PHY-1807007 and
PHY-1913789, and the US Department of Energy and research grant Nos. DE-
AC06-76RLO1830, DE-SC0007983, DE-SC0009824, DE-SC0009973, DE-SC0010073, DE-
SC0010118, DE-SC0010504, DE-SC0011784, DE-SC0012704, DE-SC0021274; and the
Vietnam Academy of Science and Technology (VAST) under grant DL0000.05/21-23.

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