Cross Section Constrained Top Quark Mass Measurement from Dilepton Events at the Tevatron

We report the first top quark mass measurement that uses a cross section constraint to improve the mass determination. This measurement is made with a dilepton $t\bar{t}$ event sample collected with the CDF II detector. From a data sample corresponding to an integrated luminosity of 1.2 fb${}^{-1}$, we measure a top quark mass of $170.7_{-3.9}^{+4.2}(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t})\pm 2.6(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})$ $\pm 2.4(\mathrm{t}\mathrm{h}\mathrm{e}\mathrm{o}\mathrm{r}\mathrm{y})\mathrm{G}\mathrm{e}\mathrm{V}\mathrm{/}{c}^2$. The measurement without the cross section constraint results in a top quark mass of $169.7_{-4.9}^{+5.2}(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t})\pm 3.1(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})\mathrm{G}\mathrm{e}\mathrm{V}\mathrm{/}{c}^2$.