Differential measurement of $\mathrm{t}\bar{\mathrm{t}}\mathrm{Z}$ production at $\sqrt{s}=13\,\mathrm{TeV}$ with the CMS experiment

Abstract

Measurements of top quark pair production in association with a Z boson ($\mathrm{t}\bar{\mathrm{t}}\mathrm{Z}$) provide direct tests of the coupling of top quarks and Z bosons, as well as the description of the production mechanism in QCD. The measurements can be used to constrain possible contributions from anomalous top quark-Z boson couplings. A first differential $\mathrm{t}\bar{\mathrm{t}}\mathrm{Z}$ production measurement has been performed by the CMS experiment using events with three leptons collected in 2016 & 2017. The differential cross sections are reported as functions of the Z boson transverse momentum, and of the angle between the Z boson and one of its decay leptons, boosted to the Z boson's rest frame. The results are compared to state-of-the-art theory predictions.