Higgs Discovery: Impact on Composite Dynamics

Preprint number: CP3-Origins-2013-24 DNRF90 and DIAS-2013-24
Author: Francesco Sannino (CP3-Origins & DIAS)
External link: arXiv.org

I discuss the impact of the discovery of a Higgs-like state on composite dynamics starting by critically examining the reasons in favour of either an elementary or composite nature of this state. Accepting the standard model interpretation I re-address the standard model vacuum stability within a Weyl-consistent computation.

I will carefully examine the fundamental reasons why what has been discovered might not be the standard model Higgs. Dynamical electroweak breaking naturally addresses a number of the fundamental issues unsolved by the standard model interpretation. However this paradigm has been challenged by the discovery of a not-so-heavy Higgs-like state. I will therefore review the recent discovery cite{Foadi:2012bb} that the standard model top-induced
radiative corrections naturally reduce the intrinsic non-perturbative mass of the composite Higgs state towards the desired experimental value. Not only we have a natural and testable working framework but we have also suggested specific gauge theories that can realise, at the fundamental level, these minimal models of dynamical electroweak symmetry breaking. By minimal I mean that the underlying gauge theories feature only one fermion doublet gauged under the electroweak symmetry even thought they can already feature (near) conformal dynamics. These strongly coupled gauge theories are now being heavily investigated via first principle lattice simulations with encouraging results.

The new findings show that the recent naive claims made about new strong dynamics at the electroweak scale being disfavoured by the discovery of a not so heavy composite Higgs are unwarranted.

I will then introduce the more speculative idea of extreme compositeness according to which not only the Higgs sector of the standard model is composite but also quarks and leptons, and provide a toy example in the form of gauge-gauge duality.