Constraints on Non-standard Top Quark Couplings

TL;DR

This paper investigates non-standard top quark couplings using effective field theory, calculating their effects on electroweak observables to derive constraints on possible new physics interactions.

Contribution

It systematically includes all nine relevant dimension-six operators and computes their tree-level and one-loop contributions to precision electroweak data.

Findings

Constraints on eight of the nine operators derived from data

Identification of dominant operators affecting electroweak observables

Quantitative bounds on non-standard top quark interactions

Abstract

We study non-standard top quark couplings in the effective field theory approach. All nine dimension-six operators that generate anomalous couplings between the electroweak gauge bosons and the third-generation quarks are included. We calculate their contributions at tree level and one loop to all major precision electroweak observables. The calculations are compared with data to obtain constraints on eight of these operators.