Abstract
The first direct search for lepton-flavour-violating decays of the recently discovered Higgs boson (H) is described. The search is performed in the H→μτe and H→μτh channels, where τe and τh are tau leptons reconstructed in the electronic and hadronic decay channels, respectively. The data sample used in this search was collected in pp collisions at a centre-of-mass energy of s=8 TeV with the CMS experiment at the CERN LHC and corresponds to an integrated luminosity of 19.7 fb−1. The sensitivity of the search is an order of magnitude better than the existing indirect limits. A slight excess of signal events with a significance of 2.4 standard deviations is observed. The p-value of this excess at MH=125 GeV is 0.010. The best fit branching fraction is B(H→μτ)=(0.84−0.37 +0.39)%. A constraint on the branching fraction, B(H→μτ)<1.51% at 95% confidence level is set. This limit is subsequently used to constrain the μ–τ Yukawa couplings to be less than 3.6×10−3.
| Original language | English |
|---|---|
| Pages (from-to) | 337-362 |
| Number of pages | 26 |
| Journal | Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics |
| Volume | 749 |
| DOIs | |
| Publication status | Published - 7 Oct 2015 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2015 CERN for the benefit of the CMS Collaboration
Funding
We congratulate our colleagues in the CERN accelerator departments for the excellent performance of the LHC and thank the technical and administrative staffs at CERN and at other CMS institutes for their contributions to the success of the CMS effort. In addition, we gratefully acknowledge the computing centres and personnel of the Worldwide LHC Computing Grid for delivering so effectively the computing infrastructure essential to our analyses. Finally, we acknowledge the enduring support for the construction and operation of the LHC and the CMS detector provided by the following funding agencies: BMWFW and FWF (Austria); FNRS and FWO (Belgium); CNPq , CAPES , FAPERJ , and FAPESP (Brazil); MES (Bulgaria); CERN ; CAS , MoST , and NSFC (China); COLCIENCIAS (Colombia); MSES and CSF (Croatia); RPF (Cyprus); MoER , ERC IUT and ERDF (Estonia); Academy of Finland , MEC , and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF , DFG , and HGF (Germany); GSRT (Greece); OTKA and NIH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); MSIP and NRF (Republic of Korea); LAS (Lithuania); MOE and UM (Malaysia); CINVESTAV , CONACYT , SEP , and UASLP-FAI (Mexico); MBIE (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland); FCT (Portugal); JINR (Dubna); MON , RosAtom , RAS and RFBR (Russia); MESTD (Serbia); SEIDI and CPAN (Spain); Swiss Funding Agencies (Switzerland); MST (Taipei); ThEPCenter , IPST , STAR and NSTDA (Thailand); TUBITAK and TAEK (Turkey); NASU and SFFR (Ukraine); STFC (United Kingdom); DOE and NSF (USA). Individuals have received support from the Marie-Curie programme and the European Research Council and EPLANET (European Union); the Leventis Foundation ; the A.P. Sloan Foundation ; the Alexander von Humboldt Foundation ; the Belgian Federal Science Policy Office ; the Fonds pour la Formation à la Recherche dans l'Industrie et dans l'Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium); the Ministry of Education, Youth and Sports ( MEYS ) of the Czech Republic; the Council of Science and Industrial Research, India ; the HOMING PLUS programme of Foundation for Polish Science , cofinanced from European Union , Regional Development Fund ; the Compagnia di San Paolo (Torino); the Consorzio per la Fisica (Trieste); MIUR project 20108T4XTM (Italy); the Thalis and Aristeia programmes cofinanced by EU-ESF and the Greek NSRF ; and the National Priorities Research Program by Qatar National Research Fund . Individuals have received support from the Marie-Curie programme and the European Research Council and EPLANET (European Union); the Leventis Foundation; the A.P. Sloan Foundation; the Alexander von Humboldt Foundation; the Belgian Federal Science Policy Office; the Fonds pour la Formation à la Recherche dans l'Industrie et dans l'Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium); the Ministry of Education, Youth and Sports (MEYS) of the Czech Republic; the Council of Science and Industrial Research, India; the HOMING PLUS programme of Foundation for Polish Science, cofinanced from European Union, Regional Development Fund; the Compagnia di San Paolo (Torino); the Consorzio per la Fisica (Trieste); MIUR project 20108T4XTM (Italy); the Thalis and Aristeia programmes cofinanced by EU-ESF and the Greek NSRF; and the National Priorities Research Program by Qatar National Research Fund.
| Funders | Funder number |
|---|---|
| CPAN | |
| Consorzio per la Fisica | |
| ERC IUT | |
| EU-ESF | |
| FRIA-Belgium | |
| IWT-Belgium | |
| MESTD | |
| MON | |
| MSES | |
| MSHE | |
| MoER | |
| STAR | |
| Swiss Funding Agencies | |
| TUBITAK | |
| UASLP-FAI | |
| National Science Foundation | 1151640, 1506168, 1206044, 1314131, 1306951, 1506130, 1120138, 1211067, 1508869 |
| National Institutes of Health | |
| U.S. Department of Energy | |
| Alfred P. Sloan Foundation | |
| Hispanics in Philanthropy | |
| Human Growth Foundation | |
| Alexander von Humboldt-Stiftung | |
| California Department of Fish and Wildlife | |
| Ministry of Science and Technology | |
| Compagnia di San Paolo | |
| Departamento Administrativo de Ciencia, Tecnología e Innovación | |
| Children's Specialists Foundation | |
| California Earthquake Authority | |
| Qatar National Research Fund | |
| Ministry of Education | |
| Secretaría de Educación Pública | |
| Türkiye Atom Enerjisi Kurumu | |
| Santa Fe Institute | |
| Louisiana Academy of Sciences | |
| Rochester Academy of Science | |
| National Research Foundation | |
| Missouri University of Science and Technology | |
| Medical Engineering Centre, King’s College London | |
| CERN | |
| University of Washington College of Arts and Sciences | |
| Thailand Center of Excellence in Physics | |
| Cosmetic Surgery Foundation | |
| Institute for the Promotion of Teaching Science and Technology | |
| Science and Technology Facilities Council | ST/L00609X/1, ST/N000250/1, ST/J004901/1, ST/K003542/1, ST/K001256/1, ST/K003844/1, GRIDPP, ST/M005356/1, ST/I505580/1, ST/I005912/1, ST/J005665/1, ST/J50094X/1, ST/K001604/1, ST/M004775/1, ST/K001639/1, ST/L005603/1 |
| European Commission | |
| European Research Council | |
| National Stroke Foundation | |
| Department of Science and Technology, Ministry of Science and Technology, India | |
| Council of Scientific and Industrial Research, India | |
| Ministry of Education - Singapore | |
| Department of Atomic Energy, Government of India | |
| Taighde Éireann - Research Ireland | |
| Helmholtz-Gemeinschaft | |
| Deutsche Forschungsgemeinschaft | |
| Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung | 153664 |
| Fundação de Amparo à Pesquisa do Estado de São Paulo | |
| National Natural Science Foundation of China | |
| Research Promotion Foundation | |
| Ministerstvo Školství, Mládeže a Tělovýchovy | |
| National Science Council | |
| Fundacja na rzecz Nauki Polskiej | |
| Fundação para a Ciência e a Tecnologia | |
| Russian Foundation for Basic Research | |
| Coordenação de Aperfeiçoamento de Pessoal de Nível Superior | |
| Academy of Finland | |
| Bundesministerium für Bildung und Forschung | |
| Chinese Academy of Sciences | |
| Austrian Science Fund | |
| Fonds De La Recherche Scientifique - FNRS | |
| Russian Academy of Sciences | |
| Federaal Wetenschapsbeleid | |
| Fonds Wetenschappelijk Onderzoek | |
| Agentschap voor Innovatie door Wetenschap en Technologie | |
| Fonds pour la Formation à la Recherche dans l’Industrie et dans l’Agriculture | |
| Consejo Nacional de Ciencia y Tecnología | |
| Ministerio de Economía y Competitividad | |
| Ministry of Education, Youth and Science | |
| Ministero dell’Istruzione, dell’Università e della Ricerca | 20108T4XTM |
| Bundesministerium für Wissenschaft, Forschung und Wirtschaft | |
| General Secretariat for Research and Technology | |
| Ministry of Business, Innovation and Employment | |
| Országos Tudományos Kutatási Alapprogramok | |
| Conselho Nacional de Desenvolvimento Científico e Tecnológico | |
| Ministry of Science, ICT and Future Planning | |
| National Research Foundation of Korea | |
| Joint Institute for Nuclear Research | |
| Instituto Nazionale di Fisica Nucleare | |
| Ministry of Science ICT and Future Planning | |
| A.G. Leventis Foundation | |
| National Science and Technology Development Agency | |
| Universiti Malaya | |
| Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro | |
| Ministry of Science and Technology, Taiwan | |
| National Academy of Sciences of Ukraine | |
| Centre National de la Recherche Scientifique | |
| Ministry of Education and Science | |
| Institute for Research in Fundamental Sciences | |
| Commissariat à l'Énergie Atomique et aux Énergies Alternatives | |
| Bundesministerium für Bildung und Frauen | |
| Secretaría de Estado de Investigación, Desarrollo e Innovación | |
| European Regional Development Fund | |
| State Atomic Energy Corporation ROSATOM | |
| Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional | |
| Pakistan Atomic Energy Commission | |
| State Fund for Fundamental Research of Ukraine | |
| Department of Science and Technology, Government of West Bengal | |
| Fundació Catalana de Trasplantament | |
| Univerza v Mariboru | |
| Institut National de Physique Nucléaire et de Physique des Particules |
Keywords
- CMS
- Higgs
- Lepton-flavour-violation
- Muons
- Physics
- Taus