Precision Determination of the Top Quark Mass

The CDF and D0 collaborations have updated their measurements of the mass of the top quark using proton-antiproton collisions at sqrt{s}=1.96TeV produced at the Tevatron. The uncertainties in each of the of top-antitop decay channels have been reduced. The new Tevatron average for the mass of the top quark based on about 1/fb of data per experiment is 170.9±1.8GeV/c^2.