Measurements of the Top Anti-Top Cross Section and the Top Quark Mass in the Hadronic tau + Jets Decay Channel at CDF

Abstract

We present the first exclusive observation of the ttbar to hadronic tau + jets decay channel. Using these events from 1.96 TeV ppbar collisions at CDF, we measure the ttbar cross section as well as the top quark mass. Events require a single hadronic tau, large missing transverse energy, and exactly 4 jets of which at least one must be tagged as a b jet. The cross section measurement is extracted from a Poisson likelihood function based on the observed number of events and the predicted number of signal and background events for a given ttbar cross section. The mass is extracted from a likelihood fit based on per-event probabilities calculated from leading-order signal (ttbar) and background (W+jets) matrix elements.