Indirect Constraints on Composite Higgs Models
Dr. David Straub (THEP)

The discovery of a Higgs-like scalar particle with a mass of 125 GeV has reinforced the need to address the gauge hierarchy problem: in the absence of supersymmetry, a fundamental scalar particle would require an unnatural amount of fine-tuning. This problem can be solved if the Higgs is a composite particle of a new strong interaction, in particular if it arises as a pseudo Nambu-Goldstone boson. But even then, a moderate degree of fine-tuning calls for relatively light fermionic resonances. Apart from direct searches for such resonances, such models are strongly constrained by electroweak precision observables and flavour physics. I will present an overview of electroweak, flavour and collider constraints on composite Higgs models, considering several choices for the electroweak representations, comparing flavour-symmetric models to flavour-anarchic ones and identifying the least fine-tuned cases and their prospects.