We search for a light Higgs boson (A0) decaying into a τ+τ- or μ+μ- pair in the radiative decays of ϒ(1S). The production of ϒ(1S) mesons is tagged by ϒ(2S)→π+π-ϒ(1S) transitions, using 158×106 ϒ(2S) events accumulated with the Belle detector at the KEKB asymmetric energy electron-positron collider. No significant A0 signals in the mass range from the τ+τ- or μ+μ- threshold to 9.2 GeV/c2 are observed. We set the upper limits at 90% credibility level (C.L.) on the product branching fractions for ϒ(1S)→γA0 and A0→τ+τ- varying from 3.8×10-6 to 1.5×10-4. Our results represent an approximately twofold improvement on the current world best upper limits for the ϒ(1S)→γA0(→τ+τ-) production. For A0→μ+μ-, the upper limits on the product branching fractions for ϒ(1S)→γA0 and A0→μ+μ- are at the same level as the world average limits, and vary from 3.1×10-7 to 1.6×10-5. The upper limits at 90% credibility level on the Yukawa coupling fϒ(1S) and mixing angle sinθA0 are also given.
|Journal||Physical review letters|
|Publication status||Published - 2022 Feb 25|
Bibliographical noteFunding Information:
We thank the KEKB group for the excellent operation of the accelerator; the KEK cryogenics group for the efficient operation of the solenoid; and the KEK computer group, and the Pacific Northwest National Laboratory (PNNL) Environmental Molecular Sciences Laboratory (EMSL) computing group for strong computing support; and the National Institute of Informatics, and Science Information NETwork 5 (SINET5) for valuable network support. We acknowledge support from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan, the Japan Society for the Promotion of Science (JSPS), and the Tau-Lepton Physics Research Center of Nagoya University; the Australian Research Council including Grants No. DP180102629, No. DP170102389, No. DP170102204, No. DP150103061, No. FT130100303; Austrian Federal Ministry of Education, Science and Research (FWF) and FWF Austrian Science Fund No. P~31361-N36; the National Natural Science Foundation of China under Contracts No. 12005040, No. 11675166, No. 11705209; No. 11975076; No. 12135005; No. 12175041; No. 12161141008; Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS), Grant No. QYZDJ-SSW-SLH011; the Shanghai Science and Technology Committee (STCSM) under Grant No. 19ZR1403000; the Ministry of Education, Youth and Sports of the Czech Republic under Contract No. LTT17020; Horizon 2020 ERC Advanced Grant No. 884719 and ERC Starting Grant No. 947006 “InterLeptons” (European Union); the Carl Zeiss Foundation, the Deutsche Forschungsgemeinschaft, the Excellence Cluster Universe, and the VolkswagenStiftung; the Department of Atomic Energy (Project Identification No. RTI 4002) and the Department of Science and Technology of India; the Istituto Nazionale di Fisica Nucleare of Italy; National Research Foundation (NRF) of Korea Grants No. 2016R1\-D1A1B\-01010135, No. 2016R1\-D1A1B\-02012900, No. 2018R1\-A2B\-3003643, No. 2018R1\-A6A1A\-06024970, No. 2019K1\-A3A7A\-09033840, No. 2019R1\-I1A3A\-01058933, No. 2021R1\-A6A1A\-03043957, No. 2021R1\-F1A\-1060423, No. 2021R1\-F1A\-1064008; 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; 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 No. 14.W03.31.0026, and the HSE University Basic Research Program, Moscow; University of Tabuk research grants S-1440-0321, S-0256-1438, and S-0280-1439 (Saudi Arabia); the Slovenian Research Agency Grants No. J1-9124 and No. P1-0135; Ikerbasque, Basque Foundation for Science, Spain; the Swiss National Science Foundation; the Ministry of Education and the Ministry of Science and Technology of Taiwan; and the United States Department of Energy and the National Science Foundation.
© 2022 authors. Published by the American Physical Society.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)