@article{10902/28333, year = {2012}, month = {12}, url = {https://hdl.handle.net/10902/28333}, abstract = {The results of a search for the pair production of a fourth-generation up-type quark (t) in proton?proton collisions at ?s = 7 TeV are presented, using data corresponding to an integrated luminosity of about 5.0 fb?1 collected by the Compact Muon Solenoid experiment at the LHC. The t quark is assumed to decay exclusively to a W boson and a b quark. Events with a single isolated electron or muon, missing transverse momentum, and at least four hadronic jets, of which at least one must be identified as a b jet, are selected. No significant excess of events over standard model expectations is observed. Upper limits for the tt¯ production cross section at 95% confidence level are set as a function of t mass, and t -quark production for masses below 570 GeV is excluded. The search is equally sensitive to nonchiral heavy quarks decaying to Wb. In this case, the results can be interpreted as upper limits on the production cross section times the branching fraction to Wb.}, organization = {We congratulate our colleagues in the CERN accelerator departments for the excellent performance of the LHC machine. We thank the technical and administrative staff at CERN and other CMS institutes, and acknowledge support from: FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (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); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA).}, publisher = {Elsevier}, publisher = {Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 2012, 718(2), 307-328}, title = {Search for pair produced fourth-generation up-type quarks in pp collisions at vs=7 TeV with a lepton in the final state}, author = {Chatrchyan, S. and Brochero Cifuentes, Javier Andrés and Cabrillo Bartolomé, José Iban and Calderón Tazón, Alicia and Chuang, S. H. and Duarte Campderros, Jorge and Felcini, Marta and Fernández García, Marcos and Gómez Gramuglio, Gervasio and González Sánchez, Francisco Javier and Graziano, Alberto and Jordá Lope, Clara and López Virto, María Amparo and Marco de Lucas, Jesús and Marco de Lucas, Rafael José and Martínez Rivero, Celso and Matorras Weinig, Francisco and Muñoz Sánchez, Francisca Javiela and Rodrigo Anoro, Teresa and Rodríguez Marrero, Ana Yaiza and Ruiz Jimeno, Alberto and Scodellaro, Luca and Vila Álvarez, Iván and Vilar Cortabitarte, Rocío}, }