Measurement of the Top Quark Mass Using Dilepton Events

The D0 Collaboration has performed a measurement of the top quark mass $m_t$ based on six candidate events for the process $t\overline{t}\to {\mathrm{bW}}^{+}\overline{b}{W}^{-}$, where the $W$ bosons decay to $e\nu$ or $\mu \nu$. This sample was collected during an exposure of the D0 detector to an integrated luminosity of $125{\mathrm{pb}}^{-1\mathrm{}}$ of $\sqrt{s}=1.8\mathrm{TeV}p\overline{p}$ collisions. We obtain $m_t=168.4\mathrm{}\pm 12.3\left(\mathrm{stat}\right)\pm 3.6\left(\mathrm{syst}\right)\mathrm{GeV}{/c}^2$, consistent with the measurement obtained using single-lepton events. Combination of the single-lepton and dilepton results yields $m_t=172.0\mathrm{}\pm 7.5\mathrm{GeV}{/c}^2$.