Top quark mass measurement from dilepton events at CDF II with the matrix-element method

Abstract

We describe a measurement of the top quark mass using events with two charged leptons collected by the CDF II detector from $p\overline{p}$ collisions with $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ at the Fermilab Tevatron. The likelihood in top quark mass is calculated for each event by convoluting the leading order matrix element describing $q\overline{q}\ensuremath{\rightarrow}t\overline{t}\ensuremath{\rightarrow}b\ensuremath{\ell}{\ensuremath{\nu}}_{\ensuremath{\ell}}\overline{b}{\ensuremath{\ell}}^{\ensuremath{'}}{\ensuremath{\nu}}_{{\ensuremath{\ell}}^{\ensuremath{'}}}$ with detector resolution functions. The presence of background events in the data sample is modeled using similar calculations involving the matrix elements for major background processes. In a data sample with integrated luminosity of $340\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$, we observe 33 candidate events and measure ${M}_{\mathrm{top}}=165.2\ifmmode\pm\else\textpm\fi{}6.1(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}3.4(\mathrm{syst}.)\text{ }\text{ }\mathrm{GeV}/{c}^{2}.$ This measurement represents the first application of this method to events with two charged leptons and is the most precise single measurement of the top quark mass in this channel.