Down-Type Fourth Generation Quarks in the Lepton plus Jets Decay Channel

In this paper, I report the search for pair production of the down-type fourth generation quark, b 0 , in a data set of 1.04fb 1 integrated luminosity from proton-proton collisions, collected by the ATLAS detector at CERN. Each b 0 decays promptly to tW in the lepton + jets channel as b 0 ! Wt ! WWb. The heavy down-type fourth generation quark decays produce high pT W bosons which can be identified by reconstructing the di-jet mass.