Related papers: The oblique S parameter in higgsless electroweak m…
We investigate the one-loop contributions to S and T oblique parameteres in gauge-Higgs unification. We show that these parameters are finite in five dimensional space-time, but are divergent in more than five dimensions. Remarkably,…
The basic ingredients of the Spontaneous Symmetry Breaking Phenomenon and of the Higgs Mechanism are reviewed in these lectures of pedagogical character. Some relevant topics related with the breaking $\gs \rightarrow U(1)_{\rm em}$ are…
We derive the S parameter of the electroweak radiative corrections in a scaled-QCD technicolour and using a Nambu-Jona Lasinio model for hadronic low energy interactions. In this framework deviations from low energy QCD can be…
A nonlinear realization of SU(2) chiral symmetry spontaneous breaking approach is developed in the composite operator formalism. A Lagrangian including quark, gluon and Goldstone boson degrees of freedom of the chiral quark model is…
We study the symmetry breaking sector of a supersymmetric left-right model based on the gauge group $SU(2)_L\times SU(2)_R\times U(1)_{B-L}$. The explicit mass matrices of neutral, singly charged and doubly charged scalars are constructed.…
The couplings of the electroweak effective theory contain information on the heavy-mass scales which are no-longer present in the low-energy Lagrangian. We build a general effective Lagrangian, implementing the electroweak chiral symmetry…
The mechanism of electroweak symmetry breaking in Little Higgs Models is analyzed in an effective field theory approach. This enables us to identify observable effects irrespective of the specific structure and content of the heavy degrees…
We present the results of a global analysis of a class of models with an extended electroweak gauge group of the form SU(2) x SU(2) x U(1), often denoted as G(221) models, which include as examples the left-right, the lepto-phobic, the…
We compute the fully differential rate for the Higgs-boson decay $h\to Z\ell^+\ell^-$, with $Z\to\ell^{'+}\ell^{'-}$. For these processes we assume the most general matrix elements within an effective Lagrangian framework. The electroweak…
In this paper I review the calculations (and partially simulations and theoretical studies) that have been made and published during the last two to three years focusing on the electroweak symmetry breaking sector and the Higgs boson(s)…
Electroweak precision observables are calculated at complete 1-loop order in the extension of the standard model by an extra Higgs triplet, where the $\rho$-parameter can be different from unity already at the tree level. One additional…
In this paper we compute the the one-loop chiral logarithmic corrections to the S and T parameters in a highly deconstructed Higgsless model with only three sites. In addition to the electroweak gauge bosons, this model contains a single…
We present a comprehensive analysis of the Higgs boson spectra in several versions of the supersymmetric left--right model based on the gauge symmetry $SU(3)_c \times SU(2)_L \times SU(2)_R \times U(1)_{B-L}$. A variety of symmetry breaking…
In the context of a strongly coupled Electroweak Symmetry Breaking, composite triplet of heavy vectors degenerate in mass belonging to the $SU(2)_{L+R}$ adjoint representation may arise from a new strong interaction invariant under the…
Within an AdS/CFT inspired model of electroweak symmetry breaking the effects of various boundary terms and modifications to the background are studied. The effect on the S precision parameter is discussed with particular attention to its…
Using a general (non-linear) effective field theory description of the Standard Model electroweak symmetry breaking, we analyse the impact on the electroweak oblique parameters of hypothetical heavy resonance states strongly coupled to the…
We study the indirect effects of new physics on the phenomenology of the recently discovered "Higgs-like" particle. In a model independent framework these effects can be parametrized in terms of an effective Lagrangian at the electroweak…
We study the renormalization of the nonlinear effective SU(2) Lagrangian up to $O(p^4)$ with spontaneous symmetry breaking. The Stueckelberg transformation, the background field gauge, the Schwinger proper time and heat kernel method, and…
Parameters of the effective chiral lagrangian (EChL) of orders $O(p^4)$ and $O(p^6)$ are extracted from low--energy behaviour of dual resonance models for $ \pi\pi$ and $\pi K$ scattering amplitudes. Dual resonance models are considered to…
This paper examines the Higgs particle self-coupling and its implications for electroweak symmetry breaking in the Standard Model. We review the current experimental constraints on the Higgs trilinear coupling and discuss the challenges in…