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

TL;DR

This paper presents a highly precise measurement of the top quark mass using dilepton decay events at CDF II, employing a likelihood method that incorporates detector resolution and initial-state radiation effects.

Contribution

The study introduces an improved likelihood approach that convolutes matrix elements with detector resolutions, enhancing the precision of top quark mass measurement in dilepton channels.

Findings

Measured top quark mass: 164.5 GeV/c^2

Achieved the most precise dilepton channel measurement

Quantified uncertainties: ±3.9 GeV/c^2 (stat) and ±3.9 GeV/c^2 (syst)

Abstract

We report a measurement of the top quark mass, M_t, in the dilepton decay channel of $t\bar{t}\to b\ell'^{+}\nu_{\ell'}\bar{b}\ell^{-}\bar{\nu}_{\ell}$ using an integrated luminosity of 1.0 fb^{-1} of p\bar{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 \pm 3.9(\textrm{stat.}) \pm 3.9(\textrm{syst.}) \mathrm{GeV}/c^2, the most precise measurement of M_t in the dilepton channel.