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 nonstandard interactions of the top quark. We investigate both the flavor-conserving and flavor-changing decay modes, including their two-body and three-body semileptonic final states. The QCD mixing among relevant operators is 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.

• Received 14 April 2014

DOI:https://doi.org/10.1103/PhysRevD.90.014008