Precision Top-Quark Mass Measurement in the Lepton+Jets Topology in pp Collisions at ¿s=1.96 TeV

We report two measurements of the top-quark mass M{sub top} using the CDF II detector at the Fermilab Tevatron in a 318 pb{sup -1} data sample of tt events in the lepton+jets final state. One method uses an event-based likelihood technique resulting in M{sub top}=173.2{sub -2.4}{sup +2.6}(stat){+-}3.2(syst) GeV/c{sup 2} or 173.2{sub -4.0}{sup +4.1} GeV/c{sup 2}. The second method reconstructs a top-quark mass in each event using the measured invariant mass of the hadronically decaying W boson to constrain the jet energy scale to obtain a value for M{sub top} of 173.5{sub -3.6}{sup +3.7}(stat){+-}1.3(syst) GeV/c{sup 2} or 173.5{sub -3.8}{sup +3.9} GeV/c{sup 2}. We take the latter, which is more precise, as our result.