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

A search is presented for heavy-quark pair production (QQ¯) under the decay hypothesis QQ¯→W+qW-q¯ with q=d, s, b for up-type Q or q=u, c for down-type Q. The search is performed with 1.04 fb-1 of integrated luminosity from pp collisions at s=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.