Top Quark Mass Measurement from Dilepton Events at CDF II

TL;DR

This paper presents a precise measurement of the top quark mass using dilepton decay events at the CDF II detector, employing a matrix-element likelihood technique to analyze 33 events from proton-antiproton collisions.

Contribution

It introduces the first application of a matrix-element method to dilepton top quark decays, achieving the most precise single measurement of the top quark mass in such events.

Findings

Measured top quark mass: 165.2 ± 6.1 (stat) ± 3.4 (syst) GeV/c^2.

Combined with other measurements, top mass: 167.9 ± 5.2 (stat) ± 3.7 (syst) GeV/c^2.

Demonstrated the effectiveness of matrix-element techniques in top quark mass measurements.

Abstract

We report a measurement of the top quark mass using events collected by the CDF II Detector from ppbar collisions at \sqrt{s} = 1.96 TeV at the Fermilab Tevatron. We calculate a likelihood function for the top mass in events that are consistent with ttbar->bbar l^- \nubar b l^+ \nu decays. The likelihood is formed as the convolution of the leading-order matrix element and detector resolution functions. The joint likelihood is the product of likelihoods for each of 33 events collected in 340 pb^{-1} of integrated luminosity, yielding a top quark mass M_t = 165.2 +- 6.1 (stat.) +- 3.4(syst.) GeV/c^2. This first application of a matrix-element technique to ttbar->bbar l^- \nubar b l^+ \nu decays gives the most precise single measurement of M_t in dilepton events. Combined with other CDF Run II measurements using dilepton events, we measure M_{t} = 167.9 +- 5.2 (stat.) +- 3.7 (syst.) GeV/c^2.