Climbing to the Top of the ATLAS 13 TeV data

Abstract

The large amount of data recorded with the ATLAS detector at the Large Hadron Collider, corresponding to 140 fb$^{-1}$ of $pp$ collisions at a centre-of-mass energy of $\sqrt{s}=13$ TeV, has brought our knowledge of the top quark to a higher level. The measurement of the top-antitop quark pair-production cross-section has reached a precision of 1.8$\% $ and the cross-section was measured differentially up to several TeV in multiple observables including the top-quark transverse momentum and top-quark-pair invariant mass. Single-top-quark production was studied in all production modes. Rare production processes where the top quark is associated with a vector boson, and four-top-quark production, have become accessible and cross-section measurements for several of these processes have reached uncertainties of around 10$\% $ or smaller. Innovative measurements of the top-quark mass and properties have also emerged, including the observation of quantum entanglement in the top-quark sector and tests of lepton-flavour universality using top-quark decays. Searches for flavour-changing neutral currents in the top-quark sector have been significantly improved, reaching branching-ratio exclusion limits ranging from $10^{-3}$ to $10^{-5}$. Many of these analyses have been used to set limits on Wilson coefficients within the effective field theory framework.