Measurements of top-quark pair to $Z$-boson cross-section ratios at $\sqrt{s}=13,8,7$TeV with the ATLAS detector

ATLAS Collaboration

Ratios of top-quark pair to $Z$-boson cross sections measured from proton--proton collisions at the LHC centre-of-mass energies of $\sqrt{s}=13$TeV, 8TeV, and 7TeV are presented by…