We report a measurement of the top quark mass, M_t, in the dilepton decay channel of $t\bar{ t}\to b\ell'^{ +}\nu_{ \ell'}\bar{ b}\ell^{ -}\bar{ \nu}_{ \ell}$ using an integrated luminosity of 1.0 fb^{ -1} of p\bar{ p} collisions collected with the CDF II detector. We apply a method that convolutes a leading-order matrix element with detector resolution functions to form event-by-event likelihoods; we have enhanced the leading-order description to describe the effects of initial-state radiation. The joint likelihood is the product of the likelihoods from 78 candidate events in this sample, which yields a measurement of M_{ t} = 164.5 \pm 3.9(\textrm{ stat.}) \pm 3.9(\textrm{ syst.}) \mathrm{ GeV}/c^2, the most precise measurement of M_t in the dilepton channel.
Categories: hep-ex