Transformer neural networks in the measurement of $t\bar{t}H$ production in the $H\,{\to}\,b\bar{b}$ decay channel with ATLAS

A measurement of Higgs boson production in association with a top quark pair in the bottom–anti-bottom Higgs boson decay channel and leptonic top final states is presented. The analysis uses 140\,\mathrm{fb}^{-1} 140 f b − 1 of 13\,\mathrm{TeV} 13 T e V proton–proton collision data collected by the ATLAS detector at the Large Hadron Collider. A particular focus is placed on the role played by transformer neural networks in discriminating signal and background processes via multi-class discriminants and in reconstructing the Higgs boson transverse momentum. These powerful multi-variate analysis techniques significantly improve the analysis over a previous measurement using the same dataset. As a result, the observed (expected) event excess over the background-only hypothesis corresponds with a significance of 4.6 (5.4) standard deviations.