Gauge/gravity dual dynamics for the strongly coupled sector of composite Higgs models

TL;DR

This paper develops a holographic model inspired by string theory to study the spectrum and dynamics of composite Higgs models, comparing results with lattice simulations and predicting properties of top partners.

Contribution

It introduces a holographic approach to analyze composite Higgs models, including meson, baryon spectra, and top partner properties, improving UV physics reflection and enabling predictions beyond lattice capabilities.

Findings

Holographic results closely match lattice data for masses and decay constants.

The model predicts additional observables not yet accessible by lattice simulations.

It demonstrates the possibility of generating realistic top quark masses within the framework.

Abstract

A holographic model of chiral symmetry breaking is used to study the dynamics plus the meson and baryon spectrum of the underlying strong dynamics in composite Higgs models. The model is inspired by top-down D-brane constructions. We introduce this model by applying it to $N_f=2$ QCD. We compute meson masses, decay constants and the nucleon mass. The spectrum is improved by including higher dimensional operators to reflect the UV physics of QCD. Moving to composite Higgs models, we impose perturbative running for the anomalous dimension of the quark condensate in a variety of theories with varying number of colors and flavours. We compare our results in detail to lattice simulations for the following theories: $SU(2)$ gauge theory with two Dirac fundamentals; $Sp(4)$ gauge theory with fundamental and sextet matter; and $SU(4)$ gauge theory with fundamental and sextet quarks. In each case, the holographic results are encouraging since they are close to lattice results for masses and decay constants. Moreover, our models allow us to compute additional observables not yet computed on the lattice, to relax the quenched approximation and move to the precise fermion content of more realistic composite Higgs models not possible on the lattice. We also provide a new holographic description of the top partners including their masses and structure functions. With the addition of higher dimension operators, we show the top Yukawa coupling can be made of order one, to generate the observed top mass. Finally, we predict the spectrum for the full set of models with top partners proposed by Ferretti and Karateev.