Exploration of SMEFT Interpretation of $t\bar{t}t\bar{t}$ Production

As part of the CERN Summer Student Programme 2022, I worked with the ATLAS Detector Collaboration. My research was affiliated with the `Non Resonant BSM in 4-tops' group, working on $t\bar{t}t\bar{t}$ cross section measurement, and new physics BSM searches using $t\bar{t}t\bar{t}$ (2 same sign lepton/3+ lepton final states) production. My specific analysis focused on the effects of SMEFT parameter introduction on the yield and shape of the nominal 4-top signal. Different center-of-mass (CM) frame variables were explored to determine which ones provided the best shape difference from the nominal signal, to provide difference on which to train future neural networks. Yield and shape comparison plots were created for many CM variables, distinguishing the nominal signal from the EFT-varied signal. The variables that were found to have the largest shape differences were those involving top quark momentum: $\Sigma P_{top}$, $minP_{top}$ and $maxP_{top}$. Future continuations of this analysis could include implementing these variables into the training of a Neural Network, namely GNNs.