We present a measurement of the top quark mass in the lepton+jets and dilepton channels of $t\bar{ t}$ decays using the template method. The data sample corresponds to an integrated luminosity of 5.6 fb$^{ -1}$ of $p\bar{ p}$ collisions at Tevatron with $\sqrt{ s}=1.96$ TeV, collected with the CDF II detector. The measurement is performed by constructing templates of three kinematic variables in the lepton+jets and two kinematic variables in the dilepton channel. The variables are two reconstructed top quark masses from different jets-to-quarks combinations and the invariant mass of two jets from the $W$ decay in the lepton+jets channel, and a reconstructed top quark mass and $m_{ T2}$, 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+jets and dilepton channels to the data yields a measured top quark mass of $M_{ top} = 172.1 \pm 1.1(stat) \pm 0.9(syst).$
Categories: hep-ex