Pinning down electroweak dipole operators of the top quark

TL;DR

This paper proposes a method to measure and constrain electroweak dipole operators of the top quark at the 13 TeV LHC by analyzing various production processes and using cross section ratios and angular correlations.

Contribution

It introduces a combined approach using cross section ratios and angular correlations to disentangle and precisely constrain top quark electroweak dipole operators, reducing uncertainties.

Findings

Significant sensitivity to anomalous couplings achieved.

Cross section ratios reduce systematic uncertainties.

Angular correlations provide additional constraints.

Abstract

We consider hadronic top quark pair production and pair production in association with a photon or a $Z$ boson to probe electroweak dipole couplings in $t\bar{b}W$, $t\bar{t}\gamma$ and $t\bar{t}Z$ interactions. We demonstrate how measurements of these processes at the 13 TeV LHC can be combined to disentangle and constrain anomalous dipole operators. The construction of cross section ratios allows us to significantly reduce various uncertainties and exploit orthogonal sensitivity between the $t\bar{t}\gamma$ and $t\bar{t}Z$ couplings. In addition, we show that angular correlations in $t\bar{t}$ production can be used to constrain the remaining $t\bar{b}W$ dipole operator. Our approach yields excellent sensitivity to the anomalous couplings and can be a further step towards precise and direct measurements of the top quark electroweak interactions.