Measurement of the top quark mass in the dilepton channel

We report a measurement of the top quark mass using six candidate events for the process $p\overline{p}\to t\overline{t}+\overrightarrow{X}{l}^{+}\nu {\mathrm{bl}}^{-}\overline{\nu }\overline{b}+X$, observed in the D0 experiment at the Fermilab $p\overline{p}$ collider. Using maximum likelihood fits to the dynamics of the decays, we measure a mass for the top quark of $m_t=168.4\mathrm{}\pm 12.3\left(\mathrm{stat}\right)\pm 3.6\left(\mathrm{syst}\right)\hspace{0.5em}\mathrm{Gev}$. We combine this result with our previous measurement in the $t\overline{t}\to l+\mathrm{jets}$ channel to obtain $m_t=172.1\mathrm{}\pm 7.1\hspace{0.5em}\mathrm{GeV}$ as the best value of the mass of the top quark measured by D0.