  We present analytical results for top-quark decay processes, in an effective
field theory beyond the Standard Model, at next-to-leading order in QCD. We
parametrize new physics effects using dimension-six operators, and consider all
operators that give rise to non-standard interactions of the top quark. We
investigate both the flavor-conserving and flavor-changing decay modes,
including their two-body and three-body semi-leptonic final states. The QCD
mixing among relevant operators are also taken into account. These results
provide all information needed for a complete model-independent study of
top-quark decay at next-to-leading order accuracy, paving the way to global
analyses for new physics effects in an effective field theory approach.
