Top quark mass measurement in the lepton+jets and dilepton channels at CDF using $m_T$2

A measurement of top quark mass at CDF will be presented using a 3.0 $fb^{-1}$ data sample in both lepton+jets and dilepton channels. In the lepton+jets channel, we determine the reconstructed top quark mass by minimizing the $\chi^{2}$ for the overconstrained kinematic system, and we also measure the hadronically decaying $W$ boson mass to provide an $in-situ$ improvement in the determination of jet energy scale. In the dilepton channel, we replace our old observable $H_T$, which is the scalar sum of transverse energy of all particles in one event, with a new observable $m_T^2$, which is used in $W$ mass measurements and SUSY searches. We find a satisfying improvement in our result of top quark mass measurement using this new observable.