Composite Higgs models after Run2

TL;DR

This paper evaluates composite Higgs models against the latest 13 TeV LHC data, constraining model parameters and identifying potential signatures to distinguish different models.

Contribution

It provides a comprehensive analysis of Higgs coupling predictions and experimental constraints on composite Higgs models after Run 2.

Findings

Robust limit on the compositeness scale f of 600 GeV.

Many models predict identical Higgs coupling modifications.

Potential to identify models through specific Higgs channel deficits.

Abstract

We assess the status of models in which the Higgs is a composite pseudo-Nambu Goldstone boson, in the light of the latest 13 TeV Run 2 Higgs data. Drawing from the extensive Composite Higgs literature, we collect together predictions for the modified couplings of the Higgs, in particular examining the different predictions for $\kappa_V$ and $\kappa_F$. Despite the variety and increasing complexity of models on the market, we point out that many independent models make identical predictions for these couplings. We then look into further corrections induced by tree-level effects such as mass-mixing and singlet VEVs. We then investigate the compatibility of different models with the data, combining the Run 1 and recent Run 2 LHC data. We obtain a robust limit on the scale $f$ of 600 GeV, with stronger limits for different choices of fermion embeddings. We also discuss how a deficit in a Higgs channel could pinpoint the type of Composite Higgs model responsible for it.