Top-quark Partial Compositeness beyond the effective field theory paradigm

TL;DR

This paper explores how top-quark interactions deviate from point-like behavior at accessible energies due to partial compositeness, introducing form factors to model these effects and analyzing their collider phenomenology.

Contribution

It proposes a simplified model with form factors for top-gluon interactions, extending beyond effective field theory descriptions.

Findings

Form factors can significantly affect top-quark production rates.

Deviations from point-like interactions may appear at relatively low energies.

Implications for collider searches of heavy top partners.

Abstract

In theories of Partial Compositeness the top quark is a mixture of a composite and an elementary state, and as a consequence its interactions with gauge bosons are expected to deviate from those of a point-like object. At sufficiently large energies, such deviations cannot be parametrized by the leading effective field theory operators and form factors (i.e. energy dependent interactions) must be introduced. In this work, we argue that such effects might appear at relatively low energies with interesting phenomenological consequences. In analogy to the proton electromagnetic interactions, we devise a simplified phenomenological model that parametrizes the top-quark interactions with gluons in terms of two form factors. We study the implications of these interactions in top-quark and heavy top-partner pair production at a hadron collider.