The Present and Future of Four Top Operators

TL;DR

This paper explores the potential of future colliders to detect non-standard four-top interactions, highlighting the significance of four-top contact operators and their implications for new physics models like composite Higgs scenarios.

Contribution

It provides a comprehensive analysis of four-top contact operators at future colliders, demonstrating their detectability and impact on new physics models, especially in high-energy collider environments.

Findings

Future 100 TeV colliders can directly test four-top contact interactions.

Electron-positron colliders can indirectly probe four-top operators through top-quark pair production.

Four-top probes offer the best sensitivity to the compositeness scale in composite Higgs models.

Abstract

We study the phenomenology of a strongly-interacting top quark at future hadron and lepton colliders, showing that the characteristic four-top contact operators give rise to the most significant effects. We demonstrate the extraordinary potential of a 100 TeV proton-proton collider to directly test such non-standard interactions in four-top production, a process that we thoroughly analyze in the same-sign dilepton and trilepton channels, and explore in the fully hadronic channel. Furthermore, high-energy electron-positron colliders, such as CLIC or the ILC, are shown to exhibit an indirect yet remarkable sensitivity to four-top operators, since these constitute, via renormalization group evolution, the leading new-physics deformations in top-quark pair production. We investigate the impact of our results on the parameter space of composite Higgs models with a strongly-coupled (right-handed) top quark, finding that four-top probes provide the best sensitivity on the compositeness scale at the future energy frontier. In addition, we investigate mild yet persisting LHC excesses in multilepton plus jets final states, showing that they can be consistently described in the effective field theory of such a new-physics scenario.