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

Abstract

We report a measurement of the top-quark mass, ${M}_{t}$, in the dilepton decay channel of $t\overline{t}\ensuremath{\rightarrow}b{\ensuremath{\ell}}^{\ensuremath{'}+}{\ensuremath{\nu}}_{{\ensuremath{\ell}}^{\ensuremath{'}}}\overline{b}{\ensuremath{\ell}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\ell}}$ using an integrated luminosity of $1.0\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of $p\overline{p}$ 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 ${M}_{t}=164.5\ifmmode\pm\else\textpm\fi{}3.9(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}3.9(\mathrm{syst}.)\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, the most precise measurement of ${M}_{t}$ in the dilepton channel.