Search for Down-Type Fourth Generation Quarks with the ATLAS Detector in Events with One Lepton and Hadronically Decaying W Bosons Aad, G. Aguilar Saavedra, Juan Antonio Atlas Collaboration Top quark Atlas detector Hadronic colliders This Letter presents a search for pair production of heavy down-type quarks decaying via b′→Wt in the lepton+jets channel, as b′b¯′→W−tW+t¯→bb¯W+W−W+W−→l±νbb¯qq¯qq¯qq¯. In addition to requiring exactly one lepton, large missing transverse momentum, and at least six jets, the invariant mass of nearby jet pairs is used to identify high transverse momentum W bosons. In data corresponding to an integrated luminosity of 1.04  fb−1 from pp collisions at s√=7  TeV recorded with the ATLAS detector, a heavy down-type quark with mass less than 480 GeV can be excluded at the 95% confidence level. 2014-02-26T12:00:05Z 2014-02-26T12:00:05Z 2012 info:eu-repo/semantics/article Aad, G.; et al. Search for Down-Type Fourth Generation Quarks with the ATLAS Detector in Events with One Lepton and Hadronically Decaying W Bosons. Physical Review Letters, 109: 032001 (2012). [http://hdl.handle.net/10481/30558] 0031-9007 1079-7114 doi: 10.1103/PhysRevLett.109.032001 http://hdl.handle.net/10481/30558 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ info:eu-repo/semantics/openAccess Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License American Physical Society