Top Quark Mass Measurement from Dilepton Events at CDF II with the Matrix-Element Method

TL;DR

This paper presents a novel matrix-element method to measure the top quark mass using dilepton events at the CDF II detector, achieving the most precise single measurement in this channel.

Contribution

It introduces the first application of the matrix-element method to dilepton events for top mass measurement, improving precision over previous techniques.

Findings

Measured top quark mass as 165.2 GeV/c^2 with 6.1 GeV/c^2 statistical uncertainty.

Achieved the most precise single measurement of top mass in dilepton channel.

Demonstrated the effectiveness of the matrix-element method in this context.

Abstract

We describe a measurement of the top quark mass using events with two charged leptons collected by the CDF II detector from $p\bar{p}$ collisions with $\sqrt s = 1.96$ TeV at the Fermilab Tevatron. The likelihood in top mass is calculated for each event by convoluting the leading order matrix element describing $q\bar{q} \to t\bar{t} \to b\ell\nu_{\ell}\bar{b}\ell'\nu_{\ell'}$ 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 pb$^{-1}$, we observe 33 candidate events and measure $M_{top} = 165.2 \pm 6.1(\textrm{stat.}) \pm 3.4(\textrm{syst.}) \mathrm{~GeV}/c^2.$ 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.