Full analysis of general non-standard tbW couplings

TL;DR

This paper investigates potential non-standard couplings affecting the top quark decay to a bottom quark and W boson using an effective-Lagrangian framework, analyzing experimental constraints from the LHC.

Contribution

It provides a comprehensive analysis of four types of dimension-6 operators with complex couplings and estimates their experimental constraints based on recent LHC data.

Findings

Constraints on couplings are weak due to opposing contributions.

All couplings are treated as complex numbers.

Analysis highlights the need for more precise measurements.

Abstract

Possible non-standard couplings which could contribute to the t -> b W process are studied based on the effective-Lagrangian approach. The corresponding effective Lagrangian consists of four kinds of dimension-6 effective operators, each of which has an independent coupling constant. In this analysis, all those couplings are treated as complex numbers and constraints on them are estimated by using recent experimental data from the LHC. We point out that the resultant constraints on those couplings are still not that strong because contributions from some couplings can work oppositely with each other.