Related papers: Indirect sensitivity to Z's in high-energy e+e- co…
We study a new confining gauge theory with fermions in a vectorial representation under the SM gauge group that allows for Yukawa interactions with the Higgs. If the fermion masses are smaller than the confinement scale this realizes a type…
Twin Higgs models are the prime illustration of neutral naturalness, where the new particles of the twin sector, gauge singlets of the Standard Model (SM), ameliorate the little hierarchy problem. In this work, we analyse phenomenological…
Several topics related to phenomenology of the Higgs sector in the supersymmetric standard model are reviewed. The upper bound of the lightest Higgs mass in the minimal supersymmetric standard model as well as extended version of it is…
I discuss the motivation and physics potential of an electron-positron linear collider with a center-of-mass energy at the 1 TeV scale, in light of what we may expect to learn with the LHC. The comparison is illustrated with examples drawn…
There are compelling reasons to think that new physics will appear at or below the TeV-scale. It is not known what form this new physics will take, however. Although The Large Hadron collider is very likely to discover new particles…
The Standard Model fit prefers values of the Higgs boson mass that are below the 114 GeV direct lower limit from LEP II. The discrepancy is acute if the 3.2 sigma disagreement for the effective weak interaction mixing angle from the two…
We analyze the coupling of CP-even and CP-odd Higgs bosons to a photon and a Z boson in extensions of the Standard Model. In particular, we study in detail the effect of charged Higgs bosons in two-Higgs doublet models, and the contribution…
The process e+e- --> W+W- provides a valuable laboratory to test the Standard Model (SM) and to search for new physics. The most general helicity amplitudes for this process require the introduction of nine form-factors which we calculate…
Naturalness arguments applied to supersymmetric theories imply a spectrum containing four light higgsinos \tz_{1,2} and \tw_1^+- with masses ~ 100-300 GeV (the closer to M_Z the more natural). The compressed mass spectrum and associated low…
General Composite Higgs models provide an elegant solution to the hierarchy problem present in the Standard Model and give an alternative pattern leading to the mechanism of electroweak (EW) symmetry breaking. We present an analysis of a…
We establish a simple yet general parameterization of Higgs-muon interactions within the effective field theory frameworks, including both the Higgs Effective Field Theory (HEFT) and the Standard Model Effective Field Theory (SMEFT). We…
The single Higgs doublet in the standard model (SM) may be the simplest way of introducing electroweak symmetry breaking, but SM extensions with more scalar doublets are not excluded. A special case of the two Higgs doublet models is the…
Virtual effects induced by new physics in rare Z decays are reviewed. Since the expected sensitivity of the giga-Z linear collider is of the order of $10^{-8}$, we emphasize the importance of any new physics effect that gives a prediction…
We extend our previous analysis of $t\bar t H, t\bar t Z, t\bar b W$ production in $e^+e^-$ collisions within the CSM (Composite Standard Model) concept of Higgs boson and top quark compositeness to the case of gluon-gluon and photon-photon…
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…
In this work we study associated production of heavy Z boson and heavy top quark in the framework of Littlest Higgs model at e^-e^+ colliders considering parameter space allowed by the electroweak precision measurments. According to the…
The trilinear Higgs self-coupling provides a unique probe of the structure of the Higgs potential and of the nature of the electroweak phase transition, and constitutes a key target for future collider experiments. Recent studies have shown…
The complementarity of $e^+e^-$ and $\gamma \gamma$ colliders to discover and explore new physics beyond the Standard Model(SM) is discussed. After briefly surveying a number of various new physics scenarios we concentrate in detail on…
We discuss the phenomenology of several Beyond the Standard Model (SM) extensions that include extended Higgs sectors. The models discussed are: the SM extended by a complex singlet field (CxSM), the 2-Higgs-Doublet Model with a…
In the absence of light Higgs bosons, the W and Z bosons become strongly interacting particles at energies of about 1 TeV. If the longitudinal W,Z components are generated by Goldstone modes associated with spontaneous symmetry breaking in…