First Direct Bound on the Total Width of the Top Quark in ppbar Collisions at sqrt(s) = 1.96 TeV

TL;DR

This paper reports the first direct experimental limit on the total decay width of the top quark, using data from proton-antiproton collisions at 1.96 TeV, constraining its decay properties.

Contribution

It provides the first direct measurement approach to bound the top quark's total decay width using reconstructed mass distributions and likelihood ratio methods.

Findings

Upper limit on top quark width: 13.1 GeV at 95% confidence level

Analyzed 955 pb^-1 of data from Tevatron ppbar collisions

Identified 253 top-antitop candidate events

Abstract

We present the first direct experimental bound on the total decay width of the top quark using 955pb^-1 of the Tevatron's ppbar collisions recorded by the Collider Detector at Fermilab. We identify 253 top-antitop pair candidate events. The distribution of reconstructed top quark mass from these events is fitted to templates representing different values of the top quark width. Using a confidence interval based on likelihood ratio ordering, we extract an upper limit at 95% C.L. of Gamma_t <13.1 GeV for an assumed top quark mass of 175 GeV/c^2.