Search for the associated production of the Higgs boson with a top-quark pair
Austrian Federal Ministry of Science, Research and Economy ; Austrian Science Fund ; Belgian Fonds de la Recherche Scientifique ; Fonds voor Wetenschappelijk Onderzoek ; 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) ; Bulgarian Ministry of Education and Science ; CERN ; Chinese Academy of Sciences, Ministry of Science and Technology, and National Natural Science Foundation of China ; Colombian Funding Agency (COLCIENCIAS) ; Croatian Ministry of Science, Education and Sport ; Croatian Science Foundation ; Research Promotion Foundation, Cyprus ; Ministry of Education and Research ; Estonian Research Council ; European Regional Development Fund, Estonia ; Academy of Finland, Finnish Ministry of Education and Culture, and Helsinki Institute of Physics ; Institut National de Physique Nucleaire et de Physique des Particules / CNRS ; Commissariat a l'Energie Atomique et aux Energies Alternatives / CEA, France ; Bundesministerium fur Bildung und Forschung ; Deutsche Forschungsgemeinschaft ; Helmholtz-Gemeinschaft Deutscher Forschungszentren, Germany ; General Secretariat for Research and Technology, Greece ; National Scientific Research Foundation ; National Innovation Office, Hungary ; Department of Atomic Energy and the Department of Science and Technology, India ; Institute for Studies in Theoretical Physics and Mathematics, Iran ; Science Foundation, Ireland ; Istituto Nazionale di Fisica Nucleare, Italy ; Korean Ministry of Education, Science and Technology ; World Class University program of NRF, Republic of Korea ; Lithuanian Academy of Sciences ; Ministry of Education ; University of Malaya (Malaysia) ; Mexican Funding Agencie (CINVESTAV) ; Mexican Funding Agencie (CONACYT) ; Mexican Funding Agencie (SEP) ; Mexican Funding Agencie (UASLP-FAI) ; Ministry of Business, Innovation and Employment, New Zealand ; Pakistan Atomic Energy Commission ; Ministry of Science and Higher Education ; National Science Centre, Poland ; Fundacao para a Ciencia e a Tecnologia, Portugal ; JINR, Dubna ; Ministry of Education and Science of the Russian Federation ; Federal Agency of Atomic Energy of the Russian Federation ; Russian Academy of Sciences, and the Russian Foundation for Basic Research ; Ministry of Education, Science and Technological Development of Serbia ; Secretaria de Estado de Investigacion ; Desarrollo e Innovacion and Programa Consolider-Ingenio, Spain ; Swiss Funding Agencie (ETH Board) ; Swiss Funding Agencie (ETH Zurich) ; Swiss Funding Agencie (PSI) ; Swiss Funding Agencie (SNF) ; Swiss Funding Agencie (UniZH) ; Swiss Funding Agencie (Canton Zurich) ; Swiss Funding Agencie (SER) ; Ministry of Science and Technology, Taipei ; Thailand Center of Excellence in Physics ; Institute for the Promotion of Teaching Science and Technology of Thailand ; Special Task Force for Activating Research ; National Science and Technology Development Agency of Thailand ; Scientific and Technical Research Council of Turkey ; Turkish Atomic Energy Authority ; National Academy of Sciences of Ukraine ; State Fund for Fundamental Researches, Ukraine ; Science and Technology Facilities Council, U.K. ; US Department of Energy ; US National Science Foundation ; 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 Foundation for Polish Science ; European Union ; Regional Development Fund ; Compagnia di San Paolo (Torino) ; Consorzio per la Fisica (Trieste) ; MIUR (Italy) ; Thalis and Aristeia programmes ; EU-ESF ; Greek NSRF ; Qatar National Research Fund ; Estonian Research CouncilIUT23-4 ; Estonian Research CouncilIUT23-6 ; MIUR (Italy)20108T4XTM ; A search for the standard model Higgs boson produced in association with a top-quark pair (t (t) over barH) is presented, using data samples corresponding to integrated luminosities of up to 5.1 fb(-1) and 19.7 fb(-1) collected in pp collisions at center-of-mass energies of 7 TeV and 8 TeV respectively. The search is based on the following signatures of the Higgs boson decay: H -> hadrons, H -> photons, and H -> leptons. The results are characterized by an observed t (t) over barH signal strength relative to the standard model cross section, mu = sigma/sigma(SM), under the assumption that the Higgs boson decays as expected in the standard model. The best fit value is mu = 2.8 +/- 1.0 for a Higgs boson mass of 125.6 GeV.