Measurements of top-quark properties at the Tevatron

TL;DR

This paper reports on various measurements of top-quark properties at the Tevatron, confirming consistency with the Standard Model and setting new limits on Lorentz invariance violation.

Contribution

It presents new measurements of top-quark decay ratios, cross sections, and limits on Lorentz invariance violation using Tevatron data, expanding the understanding of top-quark physics.

Findings

Results agree with Standard Model predictions.

No evidence of Lorentz invariance violation found.

Top quark width consistent with SM expectations.

Abstract

Recent measurements of top-quark properties at the Tevatron are presented. CDF uses data corresponding up to 9.0 fb^{-1} to measure the ratio R of the branching fractions B(t \rightarrow Wb) / B(t \rightarrow Wq), the branching fraction for top-quarks decaying into \tau leptons and the cross section for the production of an additional \gamma in t\bar{t} production. The results from all these measurements agree well with their respective Standard Model expectation. D0 uses 5.3 fb^{-1} of data to measure the t\bar{t} cross section as a function of the time. A time dependency would imply Lorentz invariance violation as implemented by the Standard Model extension. No time dependency is observed and D0 sets first limits in the top-quark sector for Lorentz invariance violation. D0 also determines indirectly the top quark width using the results of earlier measurements at D0. The measured top quark width is in agreement with the SM expectation and does not show any hints for new physics contributions.