Search for the Standard Model Higgs boson in association with top quarks and decaying to $bar{b}$ at $sqrt{s}$ = 7 TeV

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 cite{tth}. The analysis uses 4.7~fb$^{-1}$ 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 $tar{t}$ 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. No significant excess of events above the background expectation is observed.