A First Top Partner Hunter's Guide

TL;DR

This paper develops a systematic effective Lagrangian framework to describe the phenomenology of lightest top partners in composite Higgs models, linking experimental bounds to naturalness considerations.

Contribution

It introduces a simplified model approach based on symmetry and dynamical assumptions, enabling straightforward interpretation of experimental searches for top partners.

Findings

LHC bounds already probe the natural parameter space

Phenomenology described by few parameters

Framework applicable to various quantum number assignments

Abstract

We provide a systematic effective lagrangian description of the phenomenology of the lightest top-partners in composite Higgs models. Our construction is based on symmetry, on selection rules and on plausible dynamical assumptions. The structure of the resulting simplified models depends on the quantum numbers of the lightest top partner and of the operators involved in the generation of the top Yukawa. In all cases the phenomenology is conveniently described by a small number of parameters, and the results of experimental searches are readily interpreted as a test of naturalness. We recast presently available experimental bounds on heavy fermions into bounds on top partners: LHC has already stepped well inside the natural region of parameter space.