Direct and indirect signals of natural composite Higgs models

TL;DR

This paper conducts a comprehensive numerical analysis of a composite Higgs model, demonstrating its ability to satisfy multiple experimental constraints, explain recent anomalies, and predicting new resonances near current detection thresholds.

Contribution

It introduces a novel numerical technique to analyze constraints on composite Higgs models with various flavor symmetries, showing viability with low electroweak fine-tuning and explaining recent experimental anomalies.

Findings

Models can pass all constraints with sub-percent electroweak fine-tuning.

The models can explain recent anomalies in $WW$, $WZ$, $Wh$, and $B$ decays.

Predicted resonances around 1 TeV just below current LHC sensitivity.

Abstract

We present a comprehensive numerical analysis of a four-dimensional model with the Higgs as a composite pseudo-Nambu-Goldstone boson that features a calculable Higgs potential and protective custodial and flavour symmetries to reduce electroweak fine-tuning. We employ a novel numerical technique that allows us for the first time to study constraints from radiative electroweak symmetry breaking, Higgs physics, electroweak precision tests, flavour physics, and direct LHC bounds on fermion and vector boson resonances in a single framework. We consider four different flavour symmetries in the composite sector, one of which we show to not be viable anymore in view of strong precision constraints. In the other cases, all constraints can be passed with a sub-percent electroweak fine-tuning. The models can explain the excesses recently observed in $WW$, $WZ$, $Wh$ and $\ell^+\ell^-$ resonance searches by ATLAS and CMS and the anomalies in angular observables and branching ratios of rare semi-leptonic $B$ decays observed by LHCb. Solving the $B$ physics anomalies predicts the presence of a dijet or $t\bar t$ resonance around 1 TeV just below the sensitivity of LHC run 1. We discuss the prospects to probe the models at run 2 of the LHC. As a side product, we identify several gaps in the searches for vector-like quarks at hadron colliders, that could be closed by reanalyzing existing LHC data.