Common exotic decays of top partners

TL;DR

This paper explores the often overlooked exotic decay channels of top partners in composite Higgs models, highlighting their prevalence and impact on search strategies for new physics at the TeV scale.

Contribution

It introduces simplified scenarios with effective Lagrangians for exotic top partner decays, emphasizing their commonality and significance in composite Higgs models.

Findings

Exotic decays are prevalent among top partners.

Light new scalars frequently couple to top partners.

Exotic decay channels significantly influence search bounds.

Abstract

Many standard model extensions that address the hierarchy problem contain Dirac-fermion partners of the top quark, which are typically expected around the TeV scale. Searches for these vector-like quarks mostly focus on their decay into electroweak gauge bosons and Higgs plus a standard model quark. In this article, backed by models of composite Higgs, we propose a set of simplified scenarios, with effective Lagrangians and benchmarks, that include more exotic decay channels, which modify the search strategies and affect the bounds. Analysing several classes of underlying models, we show that exotic decays are the norm and commonly appear with significant rates. All these models contain light new scalars that couple to top partners with charge $5/3$, $2/3$, and $-1/3$.