Precision measurement of the top-quark mass from dilepton events at CDF II

We report a measurement of the top-quark mass, M(t), in the dilepton decay channel of tt -> bl'(+) v(l')bl(l)(-v) using an integrated luminosity of 1.0 fb(-1) of pp 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 +/- 3.9 (stat.) +/- 3.9 (syst.) GeV/c(2), the most precise measurement of Mt in the dilepton channel.