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

Abstract

We present the first direct measurement of the top-quark mass using $\ttbar$ events decaying in the hadronic $\ddot{I}„$ + 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 $\sqrt{s}=1.96TeV$ at the Fermilab Tevatron, we measure the $t\bar{t}$ cross section, $\ddot{I}{ƒ}_{t\bar{t}}$, 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 $\ddot{I}{ƒ}_{t\bar{t}}=8.8\pm 3.3(\mathrm{stat})\pm 2.2(\mathrm{syst})\mathrm{pb}$ and M${}_{top}=172.7\pm 9.3(\mathrm{stat})\pm 3.7(\mathrm{syst})GeV/c^2$.

7 pages and 2 figures, accepted for publication in Phys. Rev. Lett