Exploratory studies for the ttHH production mode in the ATLAS detector

The Higgs self-coupling, which determines the shape of the Higgs potential, is one of the building blocks of the Standard Model of Particle Physics, directly connected to the electroweak symmetry breaking mechanism and to the stability of the Universe. Searching for Higgs pair (HH) production constitutes a direct way to probe the Higgs self-coupling. The production of a top quark-antiquark pair in association with a Higgs pair (ttHH) plays a special role in this context because, even if much rarer than the gluon fusion or Vector boson fusion production modes, is very sensitive to new physics effects and has implications both on the top and on the Higgs sectors. We generate Monte-Carlo samples of both ttHH and several background processes, and simulate their detector response. After calculating a variety of variables per event, we separate the MC samples into three classes using a 3-layer Neural Net (NN). Scaling with the cross-section and integrated luminosity allows us to put new limits on ttHH production in the LHC.