Sommaire:

Despite its impressive success, the standard model (SM) of particle physics does not account for all experimental observations.
Then, the SM should not be viewed as an ultraviolet complete theory, trather as an effective description of a more fundamental theory and new physics should be introduced. In this presentation, I will follow two different approaches to new physics.
In the first one, the SM is extended by only a few new fermions, which are a common prediction of most well-motivated beyond the SM theories. The main purpose will be to identify the effect of these new fermions in light of the recent Higgs coupling measurements. The focus will be on loop-induced Higgs decays and I will show that some mechanisms allow the $h\gamma\gamma$ channel to remain SM-like as experimentally observed, while a strong departure is possible in the $h\gamma Z$ channel.
In the second part of the presentation, I will focus on composite Higgs models that aim to solve the hierarchy problem of the EW scale: the Higgs appears naturally light because it emerges as a pseudo-Nambu Goldstone boson of a spontaneously broken global symmetry.
While up to now, most of the literature considered an effective approach to the non-perturbative composite dynamics, I will rather present one well-defined ultraviolet-complete realisation.
Within the Nambu and Jona-Lasinio framework (based on the 1/N expansion), I will in particular present the spectrum of the lightest composite resonances that could be observed in the near future at the LHC.

Pour plus d'informations, merci de contacter Bizot N.