Direct Search Implications for a Custodially-Embedded Composite Top

TL;DR

This paper evaluates a composite top quark model with custodial symmetry, showing it remains viable under current experimental constraints and analyzing collider search impacts.

Contribution

It introduces and assesses a bi-doublet plus singlet top compositeness model with custodial symmetry, considering both electroweak precision data and collider constraints.

Findings

Model is compatible with current electroweak data.

Collider searches place bounds on top partner masses.

The model remains viable after Higgs discovery constraints.

Abstract

We assess current experimental constraints on the bi-doublet + singlet model of top compositeness previously proposed in the literature. This model extends the standard model's spectrum by adding a custodially-embedded vector-like electroweak bi-doublet of quarks and a vector-like electroweak singlet quark. While either of those states alone would produce a model in tension with constraints from precision electroweak data, in combination they can produce a viable model. We show that current precision electroweak data, in the wake of the Higgs discovery, accommodate the model and we explore the impact of direct collider searches for the partners of the top quark.