Four-lepton production in proton–proton collisions, pp→(Z/γ⁎)(Z/γ⁎)→ℓ+ℓ−ℓ′+ℓ′−, where ℓ,ℓ′=e or μ, is studied at a center-of-mass energy of 13 TeV with the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 2.6 fb−1. The ZZ production cross section, σ(pp→ZZ)=14.6−1.8 +1.9(stat)−0.3 +0.5(syst)±0.2(theo)±0.4(lumi)pb, is measured for events with two opposite-sign, same-flavor lepton pairs produced in the mass region 60<mℓ+ℓ−,mℓ′+ℓ′−<120 GeV. The Z boson branching fraction to four leptons is measured to be B(Z→ℓ+ℓ−ℓ′+ℓ′−)=4.9−0.7 +0.8 (stat)−0.2 +0.3 (syst)−0.1 +0.2(theo)±0.1(lumi)×10−6 for the four-lepton invariant mass in the range 80<mℓ+ℓ−ℓ′+ℓ′−<100 GeV and dilepton mass mℓ+ℓ−>4 GeV for all opposite-sign, same-flavor lepton pairs. The results are in agreement with standard model predictions.
|Original language||English (US)|
|Number of pages||24|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|State||Published - Dec 10 2016|
Bibliographical noteFunding Information:
We thank Massimiliano Grazzini and his collaborators for providing the NNLO cross section calculations. 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); COLCIENCIAS (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); 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); 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 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 program 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 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 2013/11/B/ST2/04202 , 2014/13/B/ST2/02543 and 2014/15/B/ST2/03998 , Sonata-bis 2012/07/E/ST2/01406 ; the Thalis and Aristeia programs cofinanced by EU-ESF and the Greek NSRF ; the National Priorities Research Program by Qatar National Research Fund ; the Programa Clarín-COFUND del Principado de Asturias ; the Rachadapisek Sompot Fund for Postdoctoral Fellowship , Chulalongkorn University and the Chulalongkorn Academic into Its 2nd Century Project Advancement Project (Thailand); and the Welch Foundation , contract C-1845 .