A search for the Higgs boson decaying to two b-quarks in association with a dileptonically decaying top-quark pair with the ATLAS detector

Details of a search for Higgs production in association with a top-quark pair, where the Higgs decays to two b-quarks, are presented using 20.3 fb−1 of √ s = 8 TeV data from the ATLAS detector at the LHC. Whilst the existence of the Higgs boson has been established, there has yet to be a direct observation of the Higgs boson coupling to top quarks. This search aims to provide a measurement of the top-Higgs coupling to probe the nature of the Standard Model of particle physics. Dileptonic top-quark pair events are used to measure the b-tagging efficiency on data and to search for this Higgs production mechanism. To separate the sought after signal events from the large amount of background events, the application of a technique known as the matrixelement method is presented. An investigation into the impact on the discovery significance using this technique is carried out, resulting in an 8% improvement in sensitivity relative to the nominal analysis.