Eur. Phys. J. C (2018) 78: 252
https://doi.org/10.1140/epjc/s10052-018-5720-5

Regular Article - Experimental Physics

Observation of and updated measurement of at Belle

Belle Collaboration

¹ University of the Basque Country UPV/EHU, 48080, Bilbao, Spain
² Beihang University, Beijing, 100191, China
³ Budker Institute of Nuclear Physics SB RAS, Novosibirsk, 630090, Russia
⁴ Faculty of Mathematics and Physics, Charles University, 121 16, Prague, Czech Republic
⁵ Chonnam National University, Kwangju, 660-701, South Korea
⁶ University of Cincinnati, Cincinnati, OH, 45221, USA
⁷ Deutsches Elektronen-Synchrotron, 22607, Hamburg, Germany
⁸ University of Florida, Gainesville, FL, 32611, USA
⁹ Fudan University, Shanghai, 200443, China
¹⁰ Gifu University, Gifu, 501-1193, Japan
¹¹ SOKENDAI (The Graduate University for Advanced Studies), Hayama, 240-0193, Japan
¹² Gyeongsang National University, Chinju, 660-701, South Korea
¹³ Hanyang University, Seoul, 133-791, South Korea
¹⁴ University of Hawaii, Honolulu, HI, 96822, USA
¹⁵ High Energy Accelerator Research Organization (KEK), Tsukuba, 305-0801, Japan
¹⁶ J-PARC Branch, KEK Theory Center, High Energy Accelerator Research Organization (KEK), Tsukuba, 305-0801, Japan
¹⁷ IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain
¹⁸ Indian Institute of Science Education and Research Mohali, SAS Nagar, 140306, India
¹⁹ Indian Institute of Technology Bhubaneswar, Satya Nagar, Bhubaneswar, 751007, India
²⁰ Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
²¹ Indian Institute of Technology Hyderabad, Sangareddy, Telangana, 502285, India
²² Indian Institute of Technology Madras, Chennai, 600036, India
²³ Indiana University, Bloomington, IN, 47408, USA
²⁴ Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China
²⁵ Institute of High Energy Physics, 1050, Vienna, Austria
²⁶ Institute for High Energy Physics, Protvino, 142281, Russia
²⁷ University of Mississippi, University, MS, 38677, USA
²⁸ INFN-Sezione di Napoli, 80126, Naples, Italy
²⁹ INFN-Sezione di Torino, 10125, Turin, Italy
³⁰ Advanced Science Research Center, Japan Atomic Energy Agency, Naka, 319-1195, Japan
³¹ J. Stefan Institute, 1000, Ljubljana, Slovenia
³² Kanagawa University, Yokohama, 221-8686, Japan
³³ Institut für Experimentelle Kernphysik, Karlsruher Institut für Technologie, 76131, Karlsruhe, Germany
³⁴ Kennesaw State University, Kennesaw, 30144, Georgia
³⁵ King Abdulaziz City for Science and Technology, Riyadh, 11442, Saudi Arabia
³⁶ Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
³⁷ Korea Institute of Science and Technology Information, Daejeon, 305-806, South Korea
³⁸ Korea University, Seoul, 136-713, South Korea
³⁹ Kyoto University, Kyoto, 606-8502, Japan
⁴⁰ Kyungpook National University, Daegu, 702-701, South Korea
⁴¹ École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
⁴² P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Moscow, 119991, Russia
⁴³ Faculty of Mathematics and Physics, University of Ljubljana, 1000, Ljubljana, Slovenia
⁴⁴ Ludwig Maximilians University, 80539, Munich, Germany
⁴⁵ Luther College, Decorah, IA, 52101, USA
⁴⁶ University of Malaya, 50603, Kuala Lumpur, Malaysia
⁴⁷ University of Maribor, 2000, Maribor, Slovenia
⁴⁸ Max-Planck-Institut für Physik, 80805, Munich, Germany
⁴⁹ School of Physics, University of Melbourne, Melbourne, VIC, 3010, Australia
⁵⁰ University of Miyazaki, Miyazaki, 889-2192, Japan
⁵¹ Moscow Physical Engineering Institute, Moscow, 115409, Russia
⁵² Moscow Institute of Physics and Technology, Moscow, Moscow Region, 141700, Russia
⁵³ Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan
⁵⁴ Kobayashi-Maskawa Institute, Nagoya University, Nagoya, 464-8602, Japan
⁵⁵ Nara Women’s University, Nara, 630-8506, Japan
⁵⁶ National Central University, Chung-li, 32054, Taiwan
⁵⁷ National United University, Miao Li, 36003, Taiwan
⁵⁸ Department of Physics, National Taiwan University, Taipei, 10617, Taiwan
⁵⁹ H. Niewodniczanski Institute of Nuclear Physics, 31-342, Kraków, Poland
⁶⁰ Niigata University, Niigata, 950-2181, Japan
⁶¹ Novosibirsk State University, Novosibirsk, 630090, Russia
⁶² Osaka City University, Osaka, 558-8585, Japan
⁶³ Pacific Northwest National Laboratory, Richland, WA, 99352, USA
⁶⁴ Panjab University, Chandigarh, 160014, India
⁶⁵ Peking University, Beijing, 100871, China
⁶⁶ Theoretical Research Division, Nishina Center, RIKEN, Saitama, 351-0198, Japan
⁶⁷ University of Science and Technology of China, Hefei, 230026, China
⁶⁸ Showa Pharmaceutical University, Tokyo, 194-8543, China
⁶⁹ Soongsil University, Seoul, 156-743, South Korea
⁷⁰ Stefan Meyer Institute for Subatomic Physics, 1090, Vienna, Austria
⁷¹ Sungkyunkwan University, Suwon, 440-746, South Korea
⁷² School of Physics, University of Sydney, Sydney, NSW, 2006, Australia
⁷³ Department of Physics, Faculty of Science, University of Tabuk, Tabuk, 71451, Saudi Arabia
⁷⁴ Tata Institute of Fundamental Research, Mumbai, 400005, India
⁷⁵ Department of Physics, Technische Universität München, 85748, Garching, Germany
⁷⁶ Toho University, Funabashi, 274-8510, Japan
⁷⁷ Department of Physics, Tohoku University, Sendai, 980-8578, Japan
⁷⁸ Earthquake Research Institute, University of Tokyo, Tokyo, 113-0032, Japan
⁷⁹ Department of Physics, University of Tokyo, Tokyo, 113-0033, Japan
⁸⁰ Tokyo Institute of Technology, Tokyo, 152-8550, Japan
⁸¹ Tokyo Metropolitan University, Tokyo, 192-0397, Japan
⁸² University of Torino, 10124, Turin, Italy
⁸³ Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
⁸⁴ Wayne State University, Detroit, MI, 48202, USA
⁸⁵ Yonsei University, Seoul, 120-749, South Korea

^* e-mail: shencp@phys.hawaii.edu

Received: 25 January 2018
Accepted: 8 March 2018
Published online: 23 March 2018

Abstract

We report the first observation of the charmed-strange baryon with a significance greater than 5. The is found in its decay to in decays. The measured mass and width are  MeV/ and  MeV, respectively, and the product branching fraction is . We also measure with improved precision, and search for the charmonium-like state Y(4660) and its spin partner, , in the invariant mass spectrum. No clear signals of the Y(4660) nor its spin partner are observed and the 90% credibility level (C.L.) upper limits on their production rates are determined. These measurements are obtained from a sample of pairs collected at the resonance by the Belle detector at the KEKB asymmetric energy electron–positron collider.