A matrix element analysis measurement of the top quark mass in the lepton + jets channel with an in situ jet energy scale measurement

We measure the top quark mass from $p\bar p$ collisions at 1.96 TeV at CDF in the lepton + jets channel with at least 3 $fb^{-1}$ of data. Events require a single lepton, missing transverse energy, and 4 jets of which at least one must be tagged as a b jet. We use a 2D unbinned likelihood fit based on per-event probabilities calculated from leading-order signal ($t\bar t$) and background ($W$+jets) matrix elements. Our measurement is dependent upon the energy scale of calorimeter jets, so we measure this scale in-situ by constraining the invariant mass of the two jets from to the W boson mass.