Direct top-quark decay width measurement at $\sqrt{s}=13$ TeV with the ATLAS experiment

The excellent performance of the LHC accelerator allows precise measurements of the top quark properties. A direct measurement of the top-quark decay width is presented using the full Run 2 dataset collected by the ATLAS detector at $\sqrt{s}=13$ TeV, corresponding to an integrated luminosity of $139~\textrm{fb}^{-1}$. The measurement uses a profile likelihood technique with multiple templates to minimise the impact of the systematic uncertainties. The measured width is $\Gamma_t = 1.9\pm 0.5$ GeV, in agreement with the Standard Model prediction.