Search for an L-mu - L-tau gauge boson using Z -> 4 mu events in proton-proton collisions at root s=13 TeV
WOS:000466802100054 ; A search for a narrow Z' gauge boson with a mass between 5 and 70 GeV resulting from an L-mu - L-tau U (1) local gauge symmetry is reported. Theories that predict such a particle have been proposed as an explanation of various experimental discrepancies, including the lack of a dark matter signal in direct-detection experiments, tension in the measurement of the anomalous magnetic moment of the muon, and reports of possible lepton flavor universality violation in B meson decays. A data sample of proton-proton collisions at a center-of-mass energy of 13 TeV is used, corresponding to an integrated luminosity of 77.3 fb(-1) recorded in 2016 and 2017 by the CMS detector at the LHC. Events containing four muons with an invariant mass near the standard model Z boson mass are analyzed, and the selection is further optimized to be sensitive to the events that may contain Z -> Z'mu mu -> 4 mu decays. The event yields are consistent with the standard model predictions. Upper limits of 10(-8)-10(-7) at 95% confidence level are set on the product of branching fractions B(Z -> Z'mu mu)B(Z' -> mu mu), depending on the Z' mass, which excludes a Z' boson coupling strength to muons above 0.004-0.3. These are the first dedicated limits on L-mu - L-tau models at the LHC and result in a significant increase in the excluded model parameter space. The results of this search may also be used to constrain the coupling strength of any light Z' gauge boson to muons. (C) 2019 The Author(s). Published by Elsevier B.V. ; BMWFW; FWFAustrian Science Fund (FWF); FNRSFonds de la Recherche Scientifique - FNRS; FWO (Belgium)FWO; CNPqNational Council for Scientific and Technological Development (CNPq); CAPESCAPES; FAPERJCarlos Chagas Filho Foundation for Research Support of the State of Rio de Janeiro (FAPERJ); FAPESP (Brazil)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP); MES (Bulgaria); MOST; NSFC (China)National Natural Science Foundation of China (NSFC); COLCIEN-CIAS (Colombia)Departamento Administrativo de Ciencia, Tecnologia e Innovacion Colciencias; CSF (Croatia); SENESCYT (Ecuador); MoER; ERDF (Estonia)European Union (EU); Academy of FinlandAcademy of Finland; MEC; CEAFrench Atomic Energy Commission; CNRS/IN2P3 (France)Centre National de la Recherche Scientifique (CNRS); BMBFFederal Ministry of Education & Research (BMBF); DFGGerman Research Foundation (DFG); HGF (Germany); GSRT (Greece)Greek Ministry of Development-GSRT; NKFIA (Hungary); DAEDepartment of Atomic Energy (DAE); DSTDepartment of Science & Technology (India); IPM; SFI (Ireland)Science Foundation Ireland; INFN (Italy)Istituto Nazionale di Fisica Nucleare (INFN); NRF (Republic of Korea); MOEMinistry of Higher Education & Scientific Research (MHESR); UM (Malaysia); BUAP, CINVESTAV; CONACYTConsejo Nacional de Ciencia y Tecnologia (CONACyT); UASLP-FAI (Mexico); MBIE (New Zealand); PAEC (Pakistan); MSHE; FCT (Portugal)Portuguese Foundation for Science and Technology; JINR (Dubna); RFBRRussian Foundation for Basic Research (RFBR); MESTD (Serbia); SEIDI; FEDER (Spain)European Union (EU); Swiss Funding Agencies (Switzerland); NSTDA (Thailand); TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK); TAEKMinistry of Energy & Natural Resources - Turkey; NASU; SFFR (Ukraine)State Fund for Fundamental Research (SFFR); DOEUnited States Department of Energy (DOE); NSF (USA)National Science Foundation (NSF); Marie-Curie programEuropean Union (EU); European Research CouncilEuropean Research Council (ERC); Horizon 2020 Grant [675440]; Leventis Foundation; Alfred P. Sloan FoundationAlfred P. Sloan Foundation; Alexander von Hum-boldt FoundationAlexander von Humboldt Foundation; Belgian Federal Science Policy OfficeBelgian Federal Science Policy Office; Fonds pour la Formation a la Recherche dans l'Industrie et dans l'Agriculture(FRIA-Belgium)Fonds de la Recherche Scientifique - FNRS; Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium)Institute for the Promotion of Innovation by Science and Technology in Flanders (IWT); FWO (Belgium) under the "Excellence of Science - EOSFWO [30820817]; Ministry of Education, Youth and Sports (MEYS) of the Czech RepublicMinistry of Education, Youth & Sports - Czech Republic; Janos Bolyai Research Scholarship of the Hungarian Academy of SciencesHungarian Academy of Sciences [123842, 123959, 124845, 124850, 125105]; Council of Science and Industrial Research, IndiaCouncil of Scientific & Industrial Research (CSIR) - India; HOMING PLUS program of the Foundation for Polish Science; European Union, Regional Development FundEuropean Union (EU) [Harmonia 2014/14/M/ST2/00428, 2014/13/B/ST2/02543, 2014/15/B/ST2/03998, 2015/19/B/ST2/02861]; Sonata-bis [2012/07/E/ST2/01406]; National Priorities Research Program by Qatar National Research Fund [MDM-2015-0509]; Programa Severo Ochoa del Principado de Asturias; Thalis and Aristeia programs; EU-ESFEuropean Union (EU); Greek NSRFGreek Ministry of Development-GSRT; Rachadapisek Sompot Fund for Postdoctoral Fellowship, Chulalongkorn University; Welch FoundationThe Welch Foundation [C-1845]; Weston Havens Foundation (USA); Science and Technology Facilities CouncilScience & Technology Facilities Council (STFC) [ST/M004775/1, ST/N001273/1, ST/N000242/1, ST/K003542/1 GRID PP, ST/L005603/1, ST/K003542/1] Funding Source: researchfish ; 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 centers 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); COLCIEN-CIAS (Colombia); MSES and CSF (Croatia); RPF (Cyprus); SENESCYT (Ecuador); 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); NKFIA (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); MSIP and NRF (Republic of Korea); LAS (Lithuania); MOE and UM (Malaysia); BUAP, CINVESTAV, CONACYT, LNS, 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, CPAN, PCTI and FEDER (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 program and the European Research Council and Horizon 2020 Grant, contract No. 675440 (European Union); the Leventis Foundation; the Alfred P. Sloan Foundation; the Alexander von Hum-boldt Foundation; the Belgian Federal Science Policy Office; the Fonds pour la Formation a la Recherche dans l'Industrie et dans l'Agriculture(FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium); the F.R.S.-FNRS and FWO (Belgium) under the "Excellence of Science - EOS" - be.h project n. 30820817; the Ministry of Education, Youth and Sports (MEYS) of the Czech Republic; the Lendulet ("Momentum") Program and the Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences, the New National Excellence Program UNKP, the NKFIA research grants 123842, 123959, 124845, 124850 and 125105 (Hungary); the Council of Science and Industrial Research, India; the HOMING PLUS program of the Foundation for Polish Science, cofinanced from European Union, Regional Development Fund, the Mobility Plus program of the Ministry of Science and Higher Education, the National Science Center (Poland), contracts Harmonia 2014/14/M/ST2/00428, Opus 2014/13/B/ST2/02543, 2014/15/B/ST2/03998, and 2015/19/B/ST2/02861, Sonata-bis 2012/07/E/ST2/01406; the National Priorities Research Program by Qatar National Research Fund; the Programa Estatal de Fomento de la Investigacion Cientifica y Tecnica de Excelencia Maria de Maeztu, grant MDM-2015-0509 and the Programa Severo Ochoa del Principado de Asturias; the Thalis and Aristeia programs cofinanced by EU-ESF and the Greek NSRF; the Rachadapisek Sompot Fund for Postdoctoral Fellowship, Chulalongkorn University and the Chulalongkorn Academic into Its 2nd Century Project Advancement Project (Thailand); the Welch Foundation, contract C-1845; and the Weston Havens Foundation (USA).