  A search is presented for heavy-quark pair production (QQbar) under the decay
hypothesis QQbar to WqWq with q = u,d,c,s,b. The search is performed with 1.04
fb^-1 of integrated luminosity from pp collisions at sqrt(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.
