Study of double parton scattering using W+2-jet events in proton-proton collisions at root s=7 TeV
Austrian Federal Ministry of Science and Research ; 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 ; 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 ; European Regional Development Fund, Estonia ; Academy of Finland ; Finnish Ministry of Education and Culture ; 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 ; 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 ; CINVESTAV ; CONACYT ; SEP ; 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 ; 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 ; ETH Board ; ETH Zurich ; PSI ; SNF ; UniZH ; Canton Zurich ; SER ; National Science Council, 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 ; 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 Czech Republic ; Council of Science and Industrial Research, India ; Compagnia di San Paolo (Torino) ; HOMING PLUS programme of Foundation for Polish Science ; EU ; Regional Development Fund ; EU-ESF ; Greek NSRF ; SF0690030s09 ; Double parton scattering is investigated in proton-proton collisions at = 7 TeV where the final state includes a W boson, which decays into a muon and a neutrino, and two jets. The data sample corresponds to an integrated luminosity of 5 fb(-1), collected with the CMS detector at the LHC. Observables sensitive to double parton scattering are investigated after being corrected for detector effects and selection efficiencies. The fraction of W + 2-jet events due to double parton scattering is measured to be 0.055 +/- 0.002 (stat.) +/- 0.014 (syst.). The effective cross section, sigma (eff), characterizing the effective transverse area of hard partonic interactions in collisions between protons is measured to be 20.7 +/- 0.8(stat.) +/- 6.6(syst.)mb.