Search for Higgs boson production in association with a top quark pair in pp collisions

We present a search for the Standard Model Higgs boson produced in association with top quark pairs in the 5~fb$^{-1}$ of 7 TeV $pp$ collision data collected by CMS in 2011. We look for $t\bar{t}+H$ events where the Higgs decays to $b\bar{b}$ and the top quark pair decays to either lepton plus jets ($t\bar{t} \rightarrow l\nu jjbb$) or dileptons ($t\bar{t} \rightarrow l\nu l\nu bb$). Using artificial neural networks, we achieve an expected limit of 4.6 times the standard model expectation on the $H \rightarrow b\bar{b}$ cross section for a Higgs mass of 125 GeV/c$^2$, while the observed limit is 3.8 times the standard model expectation.