Measurement of the top-quark mass in $t\bar{t} \to$ dilepton events with the ATLAS experiment using the template method in 13 TeV $pp$ collision data

This document describes the top-quark mass measurement in top-quark pair production using the full Run 2 dataset collected with the ATLAS experiment at $\sqrt{s}$=13 TeV, which amounts to 139 fb$^{-1}$. The measurement is carried out in the dilepton channel. The top-quark mass is extracted from the observed invariant mass distribution of the pair of a charged lepton and a $b$-tagged jet with the largest transverse momentum using an unbinned maximum-likelihood fit. The result is $m_{\rm top}^{dil}=172.21 \pm 0.20 \textrm{(stat)} \pm 0.67 \textrm{(syst)} \pm 0.39 \textrm{(recoil)}$ GeV.