Andrea Wulzer

The Composite Nambu-Goldstone Higgs

The composite Higgs scenario, in which the Higgs emerges as a composite pseudo-Nambu-Goldstone boson, is extensively reviewed in these Notes. The material is presented in a pedagogical fashion, with great emphasis on the conceptual and technical foundations of the construction. A comprehensive summary of the flavor, collider and electroweak precision phenomenology is also presented.

The discrete composite Higgs model

We describe a concrete, predictive incarnation of the general paradigm of a composite Higgs boson, which provides a valid alternative to the standard holographic models in five space-time dimensions. Differently from the latter, our model is four-dimensional and simple enough to be implemented in an event generator for collider studies. The model is inspired by dimensional deconstruction and hence it retains useful features of the five-dimensional scenario, in particular, the Higgs potential is finite and calculable. Therefore our setup, in spite of being simple, provides a complete description of the composite Higgs physics. After constructing the model we present a first analysis of its phenomenology, focusing on the structure of the Higgs potential, on the constraints from the EWPT and on the spectrum of the new particles.

Anomalous Couplings in Double Higgs Production

A bstractThe process of gluon-initiated double Higgs production is sensitive to nonlinear interactions of the Higgs boson. In the context of the Standard Model, studies of this process focused on the extraction of the Higgs trilinear coupling. In a general parametrization of New Physics effects, however, an even more interesting interaction that can be tested through this channel is the

Gauge-Higgs unification in orbifold models

t\overline t hh

On the interpretation of Top Partners searches

coupling. This interaction vanishes in the Standard Model and is a genuine signature of theories in which the Higgs boson emerges from a strongly-interacting sector. In this paper we perform a model-independent estimate of the LHC potential to detect anomalous Higgs couplings in gluon-fusion double Higgs production. We find that while the sensitivity to the trilinear is poor, the perspectives of measuring the new

Top partners searches and composite Higgs models

t\overline t hh

Orbifold resolutions and fermion localization

coupling are rather promising.

Setting limits on Effective Field Theories: the case of Dark Matter

Six-dimensional orbifold models where the Higgs field is identified with some internal component of a gauge field are considered. We classify all possible T-2/Z(N) orbifold constructions based on a SU(3) electroweak gauge symmetry. Depending on the orbifold twist, models with two, one or zero Higgs doublets can be obtained. Models with one Higgs doublet are particularly interesting, as they lead to a prediction for the Higgs mass that is twice the W boson mass at leading order: m(H) = 2 m(W). The electroweak scale is quadratically sensitive to the cut-off, but only through very specific localized operators. We study in detail the structure of these operators at one loop, and identify a class of models where they do not destabilize the electroweak scale at the leading order. This provides a very promising framework to construct realistic and predictive models of electroweak symmetry breaking.

Diboson interference resurrection

A bstractRelatively light Top Partners are unmistakable signatures of reasonably Natural Composite Higgs models and as such they are worth searching for at the LHC. Their phenomenology is characterized by a certain amount of model-dependence, which makes the interpretation of Top Partner experimental searches not completely straightforward especially if one is willing to take also single production into account. We describe a model-independent strategy by which the interpretation is provided on the parameter space of a Simplified Model that captures the relevant features of all the explicit constructions. The Simplified Model limits are easy to interpret within explicit models, in a way that requires no recasting and no knowledge of the experimental details of the analyses.We illustrate the method by concrete examples, among which the searches for a charge 5/3 Partner in same-sign dileptons and the searches for a charge 2/3 singlet. In each case we perform a theory recasting of the available 8 TeV Run-1 results and an estimate of the 13 TeV Run-2 reach, also including the effect of single production for which dedicated experimental analyses are not yet available. A rough assessment of the reach of a hypothetical 100 TeV collider is also provided.

On the Tuning and the Mass of the Composite Higgs

A bstractColored fermionic partners of the top quark are well-known signatures of the Composite Higgs scenario and for this reason they have been and will be subject of an intensive experimental study at the LHC. Performing an assessment of the theoretical implications of this experimental effort is the goal of the present paper. We proceed by analyzing a set of simple benchmark models, characterized by simple two-dimensional parameter spaces where the results of the searches are conveniently visualized and their impact quantified. We only draw exclusion contours, in the hypothesis of no signal, but of course our formalism could equally well be used to report discoveries in a theoretically useful format.