On the effect of resonances in composite Higgs phenomenology

TL;DR

This paper explores the phenomenology of composite Higgs models beyond the basic effective theory by introducing and analyzing the impact of low-lying resonances, focusing on their signatures in high-energy vector boson scattering.

Contribution

It proposes a simple criterion called partial UV completion to incorporate resonances into composite Higgs models and characterizes their effects on scattering signals.

Findings

Resonances cause characteristic depletion and enhancement patterns in vector boson scattering.

Derived the O(p^4) chiral Lagrangian and discussed its symmetries.

Identified simple cases with scalar and vector resonances in SO(4).

Abstract

We consider a generic composite Higgs model based on the coset SO(5)/SO(4) and study its phenomenology beyond the leading low-energy effective lagrangian approximation. Our basic goal is to introduce in a controllable and simple way the lowest-lying, possibly narrow, resonances that may exist is such models. We do so by proposing a criterion that we call partial UV completion. We characterize the simplest cases, corresponding respectively to a scalar in either singlet or tensor representation of SO(4) and to vectors in the adjoint of SO(4). We study the impact of these resonances on the signals associated to high-energy vector boson scattering, pointing out for each resonance the characteristic patterns of depletion and enhancement with respect to the leading-order chiral lagrangian. En route we derive the O(p^4) general chiral lagrangian and discuss its peculiar accidental and approximate symmetries.