We measure the top quark mass ($m_t$) in $p\overline{p}$ collisions at a center of mass energy $\sqrt{s}=1.96\mathrm{TeV}$ using dilepton $t\overline{t}\to W^{+}b{W}^{-}\overline{b}\to {\ell }^{+}{\nu }_{\ell }b{\ell }^{-}{\overline{\nu }}_{\ell }\overline{b}$ events, where $\ell$ denotes an electron, a muon, or a tau that decays leptonically. The data correspond to an integrated luminosity of $5.4{\mathrm{fb}}^{-1}$ collected with the D0 detector at the Fermilab Tevatron Collider. We obtain $m_t=174.0\pm 1.8(\mathrm{stat})\pm 2.4(\mathrm{syst})\mathrm{GeV}$, which is in agreement with the current world average $m_t=173.3\pm 1.1\mathrm{GeV}$. This is currently the most precise measurement of $m_t$ in the dilepton channel.

• Received 28 April 2011

DOI:https://doi.org/10.1103/PhysRevLett.107.082004