Search for narrow resonances in dilepton mass spectra in proton-proton collisions at root s=13 TeV and combination with 8 TeV data
BMWFW (Austria) ; FWF (Austria) ; FNRS (Belgium) ; FWO (Belgium) ; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) ; Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) ; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ; MES (Bulgaria) ; CERN ; CAS ; MoST ; NSFC (China) ; COLCIENCIAS (Colombia) ; MSES ; CSF (Croatia) ; RPF (Cyprus) ; SENESCYT (Ecuador) ; MoER ; ERC IUT ; ERDF (Estonia) ; Academy of Finland ; MEC ; HIP (Finland) ; CEA ; CNRS/IN2P3 (France) ; BMBF ; DFG ; HGF (Germany) ; GSRT (Greece) ; OTKA ; NIH (Hungary) ; DAE ; DST (India) ; IPM (Iran) ; SFI (Ireland) ; INFN (Italy) ; MSIP ; NRF (Republic of Korea) ; LAS (Lithuania) ; MOE ; UM (Malaysia) ; BUAP ; CINVESTAV ; CONACYT ; LNS ; SEP ; UASLP-FAI (Mexico) ; MBIE (New Zealand) ; PAEC (Pakistan) ; MSHE ; NSC (Poland) ; FCT (Portugal) ; JINR (Dubna) ; MON ; RosAtom ; RAS ; RFBR (Russia) ; MESTD (Serbia) ; SEIDI ; CPAN (Spain) ; Swiss Funding Agencies (Switzerland) ; MST (Taipei) ; ThEPCenter ; IPST ; STAR ; NSTDA (Thailand) ; TUBITAK ; TAEK (Turkey) ; NASU ; SFFR (Ukraine) ; STFC (United Kingdom) ; DOE ; NSF (USA) ; Marie-Curie programme ; European Research Council ; EPLANET (European Union) ; Leventis Foundation ; A.P. Sloan Foundation ; Alexander von Humboldt Foundation ; Belgian Federal Science Policy Office ; Fonds pour la Formation a la Recherche dans l'Industrie et dans l'Agriculture (FRIA-Belgium) ; Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium) ; Ministry of Education, Youth and Sports (MEYS) of the Czech Republic ; Council of Science and Industrial Research, India ; HOMING PLUS programme of the Foundation for Polish Science ; European Union, Regional Development Fund ; Mobility Plus programme of the Ministry of Science and Higher Education ; National Science Center (Poland) ; EU-ESF ; Greek NSRF ; Qatar National Research Fund ; Programa Clarin-COFUND del Principado de Asturias ; Rachadapisek Sompot Fund ; Chulalongkorn University ; Chulalongkorn Academic ; Welch Foundation ; Science and Technology Facilities Council ; National Science Center (Poland): Harmonia 2014/14/M/ST2/00428 ; National Science Center (Poland): Opus 2013/11/B/ST2/04202 ; National Science Center (Poland): 2014/13/B/ST2/02543 ; National Science Center (Poland): 2014/15/B/ST2/03998 ; National Science Center (Poland): Sonata-bis 2012/07/E/ST2/01406 ; Welch Foundation: C-1845 ; Science and Technology Facilities Council: ST/N000250/1 ; Science and Technology Facilities Council: GRIDPP ; Science and Technology Facilities Council: ST/K001256/1 ; Science and Technology Facilities Council: CMS ; A search for narrow resonances in dielectron and dimuon invariant mass spectra has been performed using data obtained from proton-proton collisions at root s = 13 TeV collected with the CMS detector. The integrated luminosity for the dielectron sample is 2.7 fb(-1) and for the dimuon sample 2.9 fb(-1). The sensitivity of the search is increased by combining these data with a previously analyzed set of data obtained at root s = 8 TeV and corresponding to a luminosity of 20 fb(-1). No evidence for non-standard-model physics is found, either in the 13 TeV data set alone, or in the combined data set. Upper limits on the product of production cross section and branching fraction have also been calculated in a model-independent manner to enable interpretation in models predicting a narrow dielectron or dimuon resonance structure. Limits are set on the masses of hypothetical particles that could appear in new-physics scenarios. For the Z'(SSM) particle, which arises in the sequential standard model, and for the superstring inspired Z'(psi) particle, 95% confidence level lower mass limits for the combined data sets and combined channels are found to be 3.37 and 2.82 TeV, respectively. The corresponding limits for the lightest Kaluza-Klein graviton arising in the Randall-Sundrum model of extra dimensions with coupling parameters 0.01 and 0.10 are 1.46 and 3.11 TeV, respectively. These results significantly exceed the limits based on the 8 TeV LHC data. (C) 2017 The Author. Published by Elsevier B.V.