Search for fourth generation quarks in the dilepton channel at ATLAS with $\sqrt{s}$ = 7 TeV

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 Large Hadron Collider (LHC). Events are selected with two oppositely-charged leptons (e or mu), 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.