Wednesday 16 May 2018 Speaker: Johnny Raine (University of Manchester) Title: "A search for ttH(bb) production with the ATLAS experiment” Abstract: After the discovery of the Higgs boson in 2012 by the ATLAS and CMS collaborations, attention has turned to more detailed measurements of its properties and couplings as a means of testing the Standard Model. In the search for the Higgs boson produced in association with a top quark pair (ttH), which has not yet been observed in data, a direct observation of the top-Higgs coupling is possible, which could provide a window into the scale of new physics and the stability of the universe. I will give an overview of the search for ttH in the H->bb decay channel, which has the largest branching ratio. I will describe how b-tagging of jets is used to select and classify events, as well as the multivariate analysis strategy employed to enhance the sensitivity of the analysis. The results of the analysis, and the combination with other Higgs boson decay channels, will be presented.