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Measurements of the Top-quark Mass and the ttbar Cross Section in the Hadronic tau + Jets Decay Channel at sqrt(s) = 1.96 TeV

We present the first direct measurement of the top-quark mass using $\ttbar$ events decaying in the hadronic $τ$ + jets decay channel. Using data corresponding to an integrated luminosity of 2.2 fb$^{-1}$ collected by the CDF II detector in $p\bar{p}$ collisions at $\sqrt{s}=1.96 ~TeV$ at the Fermilab Tevatron, we measure the $t\bar{t}$ cross section, $σ_{t\bar{t}}$, and the top-quark mass, M$_{top}$. We extract M$_{top}$ from a likelihood based on per-event probabilities calculated with leading-order signal and background matrix elements. We measure $σ_{t\bar{t}} = 8.8 \pm 3.3 ~(\mathrm{stat}) \pm 2.2 ~(\mathrm{syst}) ~\mathrm{pb}$ and M$_{top} = 172.7 \pm 9.3 ~(\mathrm{stat}) \pm 3.7 ~(\mathrm{syst}) ~GeV/c^2$.