Direct measurement of the top quark mass

▪ Abstract We review the direct measurements of the top quark mass Mt using the sample of events collected by the DO and CDF experiments at Fermilab. Measurements using events in the lepton plus jets, dilepton, and all-hadronic decay modes are reviewed, as is the combination of the results to yield the current world average Mt = 174.3 ± 3.2 (stat.) ± 4.0 (syst.) GeV/c2. We close by estimating the precision attainable with future data sets at Fermilab and the Large Hadron Collider.