Measurement of the Top Quark Mass with a Matrix Element Method in the   Lepton Plus Jets Channel at CDF
  We present a measurement of the mass of the top quark from ppbar collisions at 1.96 TeV observed with the Collider Detector at Fermilab (CDF) at the Fermilab Tevatron Run II. The events have the decay signature of ppbar to ttbar in the lepton plus jets channel in which at least one jet is identified as coming from a secondary vertex and therefore a b-hadron. The largest systematic uncertainty, the jet energy scale (JES), is convoluted with the statistical error using an in-situ measurement of the hadronic W boson mass. We calculate a likelihood for each event using leading-order ttbar and W+jets cross-sections and parameterized parton showering. The final measured top quark mass and JES systematic is extracted from a joint likelihood of the product of individual event likelihoods. From 118 events observed in 680 pb-1 of data, we measure a top quark mass of 174.09 +- 2.54 (stat+JES) +- 1.35 (syst) GeV/c2. 
Brian Mohr (for the CDF Collaboration)