Measurements of the $\text{t}\bar{\text{t}}\text{H}(\text{b}\bar{\text{b}})$ Process with Neural Networks at the CMS Experiment - Current Status and Future Prospects

This thesis presents a measurement of the production of a standard model Higgs boson in association with a top quark-antiquark pair where the Higgs boson is required to decay into a bottom quark-antiquark pair (\(\text{t}\bar{\text{t}}\text{H}(\text{b}\bar{\text{b}})\)). The results are based on data recorded at the CMS experiment in the years from 2016 to 2018, corresponding to an integrated luminosity of \(137.5\,\text{fb}^{-1}\). In particular, the semileptonic (SL) decay mode of the \(\text{t}\bar{\text{t}}\) system is discussed. The strategy for the discrimination of signal and background events is based on the multiplicity of b-tagged jets and an event categorization performed by feed-forward neural networks. At the time of writing this thesis, final tests for the estimation of the signal strength are performed. Therefore, the sensitivity expected within the scope of the Standard Model prediction is discussed, which corresponds to an expected significance of \(3.3\,\sigma\) in the SL channel. Moreover, the results are reinterpreted in the scope of the STXS measurement, where the cross sections in five \(p_\text{T}(\text{H})\) bins are estimated simultaneously. The expected results from the STXS interpretation are used to conduct first feasibility studies of measurements of effects beyond the SMEFT for the \(\text{t}\bar{\text{t}}\text{H}(\text{b}\bar{\text{b}})\) process within the CMS experiment. Finally, the sensitivity for \(\text{t}\bar{\text{t}}\text{H}(\text{b}\bar{\text{b}})\) measurements with future data sets is discussed, which is expected to reach approximately \(7\,\%\) with the estimated amount of data collected by the end of the High Luminosity LHC.