Search for the Standard Model Higgs boson in association with top quarks and decaying to bb at sqrt(s) = 7 TeV using the ATLAS detector

Abstract. A search for a Higgs boson produced in association with a pair of top quarks and decaying into a pair of b quarks is presented. The analysis uses 4.7 iffb of pp collisions at sqrt(s) =7 TeV collected in 2011 with the ATLAS detector. The search is focused on the semileptonic decay of the tt system and combines nine different topologies given by the jet and b-tagged jet multiplicities of the event. A kinematic reconstruction of the Higgs boson mass is performed in the signal enhanced region, which becomes the primary discriminant variable between signal and background. Background-dominated samples are exploited to constrain the leading systematic uncertainties affecting the background prediction. No significant excess of events above the background expectation is observed.