Search for a supersymmetric partner of the top quark in final states with jets and missing transverse momentum at sqrt{s}=7 TeV with the ATLAS detector

A search for direct pair production of supersymmetric top squarks (stop) is presented, assuming the stop decays into a top quark and the lightest supersymmetric particle or LSP (chi^0), and that both top quarks decay with purely hadronic final states. A total of 16 (4) events are observed compared to a predicted Standard Model background of 13.5 +3.7/-3.6 (4.4 +1.7/-1.3) events in two signal regions based on int Ldt = 4.7 fb-1 of pp collision data taken at sqrt{s}=7 TeV. An exclusion region in the stop versus chi^0 mass plane is evaluated; 370<m_stop<465 GeV is excluded for m_chi^0 ~ 0 GeV while m_stop=445 GeV is excluded for m_chi^0 below 50 GeV.