The top-quark window on compositeness at future lepton colliders

TL;DR

This paper explores how future lepton colliders can effectively probe composite Higgs models by analyzing top-quark pair production, revealing significant sensitivity to new physics in the top sector at TeV energies.

Contribution

It demonstrates the potential of precision measurements of top and bottom quarks at future colliders to constrain composite Higgs models using effective field theory.

Findings

Significant portion of composite Higgs parameter space can be probed.

Top portal measurements are especially sensitive at TeV energies.

Future lepton colliders offer promising avenues for new physics discovery.

Abstract

In composite Higgs (CH) models, large mixings between the top quark and the new strongly interacting sector are required to generate its sizeable Yukawa coupling. Precise measurements involving top as well as left-handed bottom quarks therefore offer an interesting opportunity to probe such new physics scenarios. We study the impact of third-generation-quark pair production at future lepton colliders, translating prospective effective-field-theory sensitivities into the CH parameter space. Our results show that one can probe a significant fraction of the natural CH parameter space through the top portal, especially at TeV centre-of-mass energies.