Combined search for electroweak production of charginos and neutralinos in proton-proton collisions at ?s=13 TeV

Abstract

2-s2.0-85045087730 ; A statistical combination of several searches for the electroweak production of charginos and neutralinos is presented. All searches use proton-proton collision data at s=13 TeV, recorded with the CMS detector at the LHC in 2016 and corresponding to an integrated luminosity of 35.9 fb?1. In addition to the combination of previous searches, a targeted analysis requiring three or more charged leptons (electrons or muons) is presented, focusing on the challenging scenario in which the difference in mass between the two least massive neutralinos is approximately equal to the mass of the Z boson. The results are interpreted in simplified models of chargino-neutralino or neutralino pair production. For chargino-neutralino production, in the case when the lightest neutralino is massless, the combination yields an observed (expected) limit at the 95% confidence level on the chargino mass of up to 650 (570) GeV, improving upon the individual analysis limits by up to 40 GeV. If the mass difference between the two least massive neutralinos is approximately equal to the mass of the Z boson in the chargino-neutralino model, the targeted search requiring three or more leptons obtains observed and expected exclusion limits of around 225 GeV on the second neutralino mass and 125 GeV on the lightest neutralino mass, improving the observed limit by about 60 GeV in both masses compared to the previous CMS result. In the neutralino pair production model, the combined observed (expected) exclusion limit on the neutralino mass extends up to 650–750 (550–750) GeV, depending on the branching fraction assumed. This extends the observed exclusion achieved in the individual analyses by up to 200 GeV. The combined result additionally excludes some intermediate gaps in the mass coverage of the individual analyses.[Figure not available: see fulltext.] © 2018, The Author(s). ; 2012/07/E/ST2/01406, 2014/13/B/ST2/02543, 2014/14/M/ST2/00428, 2014/15/B/ST2/03998, 2015/19/B/ST2/02861 National Science Foundation, NSF: 1151640, 1506130, 1506168, 1508869, 1606321, 1607202 National Institutes of Health, NIH U.S. Department of Energy, USDOE Alfred P. Sloan Foundation Welch Foundation: C-1845 Hispanics in Philanthropy, HIP CS Fund, CSF Alexander von Humboldt-Stiftung California Earthquake Authority, CEA Qatar National Research Fund, QNRF Secretaría de Educación Pública, SEP Türkiye Atom Enerjisi Kurumu, TAEK Horizon 2020 Framework Programme, H2020: 675440 Weston Havens Foundation Louisiana Academy of Sciences, LAS Missouri University of Science and Technology, MST CERN College of Arts and Sciences, University of Nebraska-Lincoln, CAS Norwegian Sequencing Centre, NSC Institute for the Promotion of Teaching Science and Technology, IPST Mountain Equipment Co-operative, MEC Science and Technology Facilities Council, STFC: ST/N000242/1 Royal Astronomical Society, RAS European Commission, EC European Research Council, ERC Ministry of Education - Singapore, MOE Department of Atomic Energy, Government of India, ???? Science Foundation Ireland, SFI Helmholtz-Gemeinschaft, HGF Deutsche Forschungsgemeinschaft, DFG Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, SNF: 166294 Fundação de Amparo à Pesquisa do Estado de São Paulo, FAPESP National Natural Science Foundation of China, NSFC Research Promotion Foundation, ???? Ministerstvo Školství, Mláde?e a T?lov?chovy, MŠMT Fundacja na rzecz Nauki Polskiej, FNP Fundação para a Ciência e a Tecnologia, FCT Russian Foundation for Basic Research, ???? Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES Academy of Finland Bundesministerium für Bildung und Forschung, BMBF Austrian Science Fund, FWF Fonds De La Recherche Scientifique - FNRS, FNRS Belgian Federal Science Policy Office, BELSPO Chulalongkorn University, CU Fonds Wetenschappelijk Onderzoek, FWO Agentschap voor Innovatie door Wetenschap en Technologie, IWT Fonds pour la Formation à la Recherche dans l'Industrie et dans l'Agriculture, FRIA Consejo Nacional de Ciencia y Tecnología, CONACYT Bundesministerium für Wissenschaft, Forschung und Wirtschaft, BMWFW General Secretariat for Research and Technology, GSRT Hungarian Scientific Research Fund, OTKA Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq Ministry of Science, ICT and Future Planning, MSIP Ministry of Science and Technology, MOST National Research Foundation of Korea, NRF Joint Institute for Nuclear Research, JINR Instituto Nazionale di Fisica Nucleare, INFN A.G. Leventis Foundation National Science and Technology Development Agency, ????: Thailand Secretaría de Educación Superior, Ciencia, Tecnología e Innovación, SENESCYT Universiti Malaya, UM Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, FAPERJ Ministry for Business Innovation and Employment, MBIE National Academy of Sciences of Ukraine, NASU Ministry of Education and Science, MES Institute for Research in Fundamental Sciences, IPM Benemérita Universidad Autónoma de Puebla, BUAP Secretaría de Estado de Investigación, Desarrollo e Innovación, SEIDI Horizon 2020 European Regional Development Fund, FEDER State Atomic Energy Corporation ROSATOM, ROSATOM Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, CINVESTAV Pakistan Atomic Energy Commission, PAEC State Fund for Fundamental Research of Ukraine, SFFR Department of Science and Technology, Government of West Bengal, DST ; Open Access, Copyright CERN, for the benefit of the CMS Collaboration. Article funded by SCOAP3. ; 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); COL-CIENCIAS (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, RFBR and RAEP (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).