Prospects for $t\overline{t}Z$ measurements at ATLAS with the full LHC Run 2 dataset

Abstract

We review the recent measurement of the inclusive $t\overline{t}Z$ cross-section with $36{\mathrm{fb}}^{-1}$ of data at 13 TeV at the ATLAS experiment, using EFT considerations and background modelling for generic SUSY/DM searches as motivation for continuing to improve the precision of this result. We then present plans for a differential $t\overline{t}Z$ measurement in the 3 and 4 lepton channels with the full $140{\mathrm{fb}}^{-1}$ Run 2 dataset, and highlight a number of promising research directions, such as a re-interpretation in terms of $t\overline{t}Z$ spin correlation observables, or the possibility to unfold SUSY/DM validation regions (or even null-result signal regions) to constrain the $t\overline{t}Z(\to \nu \overline{\nu })$ process. Particular attention is also given to the topic of semi-leptonic top reconstruction, necessary to match the performance of the dileptonic decay channels.

Baptiste Ravina

Senior Research Fellow

I’m an experimental particle physicist looking for new physics at the ATLAS experiment with machine learning.