# Improving Fine-tuning in Composite Higgs Models

## TL;DR

This paper explores a next-to-minimal composite Higgs model with a SO(6)/SO(5) coset, analyzing how Higgs-singlet mixing affects resonance masses and Higgs couplings, with implications for LHC searches.

## Contribution

It demonstrates that Higgs-singlet mixing in this model allows for heavier top-partners and relaxes LHC bounds compared to minimal models.

## Key findings

- Higgs-singlet mixing can accommodate heavier resonances.
- Deviations in Higgs couplings from SM predictions are significant.
- Future precision Higgs measurements will constrain the model tightly.

## Abstract

In this paper we investigate the next-to-minimal composite Higgs model with a SO(6)/SO(5) coset, whose pNGB sector includes a Standard Model singlet in addition to the usual Higgs doublet. The fermions are embedded in the representation 6 of SO(6). We study the region of parameter space of the model where the radiatively generated potential has global minima with both the doublet and the singlet fields developing vacuum expectation values. We investigate the consequences of kinetic and mass mixing between the Higgs and the singlet scalar that arise in this framework. We demonstrate that the ensuing doublet-singlet mixing can provide a handle to accommodate heavier resonances (top-partners) for a given compositeness scale as compared to the minimal composite Higgs model, thus relaxing the tension with the direct LHC bounds. The main phenomenological consequence of this is a sizable deviation of the Higgs couplings from the Standard Model predictions. While the present experimental precision in the measurement of the Higgs couplings still allows for considerable release of this tension, future measurements of the Higgs branching ratios with increased precision would lead to stringent constraints on this setup.