We present a measurement of the top quark mass in the lepton þ jets and dilepton channels of tt decays
using the data sample corresponding to an integrated luminosity of 5:6 fb1 of pp collisions at Tevatron
with
ffiffiffis
p
¼ 1:96 TeV, collected with the CDF II detector. We construct templates of two reconstructed top
quark masses from different jets-to-quarks combinations and the invariant mass of two jets from the W
decays in the lepton þ jets channel, and a reconstructed top quark mass and mT2, a variable related to the
transverse mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the
templates from signal and background events in the lepton þ jets and dilepton channels to the data yields a