Search for pair-produced heavy quarks decaying to Wq in the two-lepton channel at sqrt[(]s)=7  TeV with the ATLAS detector

A search is presented for heavy-quark pair production (Q Q) under the decay hypothesis Q Q ! WþqW q with q ¼ d, s, b for up-type Q or q ¼ u, c for down-type Q. The search is performed with 1:04 fb1 of integrated luminosity from pp collisions at pffisffiffi ¼ 7 TeV collected by the ATLAS
detector at the CERN LHC. Dilepton final states are selected, requiring large missing transverse
momentum and at least two jets. Mass reconstruction of heavy-quark candidates is performed by
assuming that the W boson decay products are nearly collinear. The data are in agreement with standard model expectations; a heavy quark with mass less than 350 GeV is excluded at 95% confidence
level.