Top quark mass and properties at D⊘ An optimized method to extract top quark properties

Dempty set has developed an optimized method to extract information on top quark properties. An Extended-Maximum-Likelihood method is used, where the event probabilities are obtained by convoluting the differential cross section with the resolution and acceptance of the detector. This method is used to remeasure the top quark mass in the lepton + jets t (t) over bar sample collected by the DO experiment during Run 1 of the Fermilab Tevatron. A new preliminary measurement of the top quark mass of M-t = 180.1 +/- 3.6(stat) +/- 4.0(sys) GeV is obtained, corresponding to a significant reduction in uncertainty on M-t. The method used can also be applied to other properties of the top quark, such as the polarization of the W's in top decays.