Event shapes and azimuthal correlations in Z+jets events in pp collisions at s=7 TeV

Abstract

Measurements of event shapes and azimuthal correlations are presented for events where a Z boson is produced in association with jets in proton-proton collisions. The data collected with the CMS detector at the CERN LHC at s=7 TeV correspond to an integrated luminosity of 5.0 fb-1. The analysis provides a test of predictions from perturbative QCD for a process that represents a substantial background to many physics channels. Results are presented as a function of jet multiplicity, for inclusive Z boson production and for Z bosons with transverse momenta greater than 150 GeV, and compared to predictions from Monte Carlo event generators that include leading-order multiparton matrix-element (with up to four hard partons in the final state) and next-to-leading-order simulations of Z+1-jet events. The experimental results are corrected for detector effects, and can be compared directly with other QCD models. © 2013 CERN ; California Earthquake Authority Serbia Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro Fuel Cell Technologies Program, FCT Joint Institute for Nuclear Research, JINR: Ukraine Marketing Science Institute Bundesministerium für Wissenschaft und Forschung, BMWF Pakistan Atomic Energy Commission: Pakistan Consejo Nacional de Ciencia y Tecnología National Science and Technology Development Agency: Thailand Institute for Research in Fundamental Sciences Hispanics in Philanthropy California Department of Fish and Game National Research Foundation Secretaría de Estado de Investigación, Desarrollo e Innovación Centers for Medicare and Medicaid Services U.S. Department of Energy Academy of Finland Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Türkiye Atom Enerjisi Kurumu Ministerio de Educación y Cultura Taipei Research Promotion Foundation: Cyprus, SF0690030s09 National Science Foundation Science and Technology Facilities Council Human Growth Foundation Croatia Austrian Science Fund Fundação de Amparo à Pesquisa do Estado de São Paulo Secretaría de Educación Pública Western Carolina University Fonds De La Recherche Scientifique - FNRS National Academy of Sciences of Ukraine Bundesministerium für Bildung und Forschung National Natural Science Foundation of China Instituto Nazionale di Fisica Nucleare Hungarian Scientific Research Fund Department of Atomic Energy, Government of India Rochester Academy of Science Department of Science and Technology, Government of Rajasthan Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq ?????????? ???? ??????????????? ???????????? (????) Center for African Studies Departamento Administrativo de Ciencia, Tecnología e Innovación, COLCIENCIAS Ministerstvo Školství, Mládeze a Telovychovy, Not Available Nemzeti Kutatási és Technológiai Hivatal, NKTH: Hungary European Regional Development Fund CERN NSC General Secretariat for Research and Technology, GSRT Fonds Wetenschappelijk Onderzoek Santa Fe Institute Louisiana Academy of Sciences ; 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: BMWF and FWF (Austria); FNRS and FWO (Belgium); CNPq , CAPES , FAPERJ , and FAPESP (Brazil); MEYS (Bulgaria); CERN ; CAS , MoST , and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); MoER , SF0690030s09 and ERDF (Estonia); Academy of Finland , MEC , and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF , DFG , and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Republic of Korea); LAS (Lithuania); CINVESTAV , CONACYT , SEP , and UASLP-FAI (Mexico); MSI (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MON , RosAtom , RAS and RFBR (Russia); MSTD (Serbia); SEIDI and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); ThEPCenter , IPST and NSTDA (Thailand); TUBITAK and TAEK (Turkey); NASU (Ukraine); STFC (United Kingdom); DOE and NSF (USA). --