Related papers: Spectra, triple and quartic gauge couplings in a H…
Using asymptotic helicity amplitudes for Vector-Vector, Vector-Higgs and Higgs-Higgs scattering, we establish the unitarity constraints on the $SU(2)_c$ conserving and $W_\mu$ depending interactions, which at sufficiently high energies may…
In a recent paper, we introduced a new Little Higgs model, which contains the gauge structure $SU(2)^3\times U(1)$, embedded in an approximate global $SO(5)\times SO(5)$ symmetry. After breaking to the standard model, $SU(2)_L \times…
After the discovery of a Higgs boson at the LHC, the next important step is to measure its couplings to fermions and bosons to unravel its true nature. In order to ultimately test the shape of the scalar potential that triggers the…
The discovery of Standard-Model like Higgs at 125 GeV may raise more questions than the answers it provides. In particular, the hierarchy problem remains unsolved, and the Standard Model Higgs quartic self-coupling becomes negative below…
We address the effect of an anomalous triple gauge boson couplings on a physical observable for the electroweak sector of the Standard Model, when the $SU(2)_{L}\otimes U(1)_{Y}$ symmetry is spontaneously broken by the Higgs mechanism to…
The type-I two-Higgs-doublet model in the inverted Higgs scenario can retain the theoretical stability all the way up to the Planck scale. The Planck-cutoff scale, $\Lambda_{\rm cut}^{\rm Planck}$, directly impacts the mass spectra such…
We study the evolution of the gauge coupling constants in string unification schemes in which the light spectrum below the compactification scale is exactly that of the minimal supersymmetric standard model. In the absence of string…
In this talk I discuss extended Higgs sectors in which the 125 GeV Higgs boson couplings to W and Z bosons can be larger than in the Standard Model. Constraints from perturbative unitarity and the electroweak rho parameter limit the number…
We study the phenomenology of the 4-site Higgsless model, based on the $SU(2)_L\times SU(2)_1\times SU(2)_2\times U(1)_Y$ gauge symmetry, at present colliders. The model predicts the existence of two neutral and four charged extra gauge…
We study the impact of LEP2 constraints on the dimensionless coefficients of the electroweak chiral Lagrangian on the precision observables using the improved renormalization group equations. We find that the current uncertainty in the…
We investigate the limits on the higgs mass in variations of Split Supersymmetry, where the boundary value of the Higgs quartic coupling at the SUSY breaking scale ($m_s$) is allowed to deviate from its value in the minimal model of…
We scan the complete parameter space of the supersymmetric standard model extended by a gauge singlet, which is compatible with the following constraints: universal soft supersymmetry breaking terms at the GUT scale, finite running Yukawa…
In the absence of a Higgs boson, the perturbative description of the Standard Model ceases to make sense above a TeV. Heavy spin-1 fields coupled to W and Z bosons can extend the validity of the theory up to higher scales. We carefully…
We study the phenomenological consequences of a four site Higgsless model based on the SU(2)_L x SU(2)_1 x SU(2)_2 x U(1)_Y gauge symmetry, which predicts two neutral and four charged extra gauge bosons, Z_{1,2} and W_{1,2}. The model…
We study coupling constants of the standard model like Higgs boson with the gauge bosons $hZZ$ and $hWW$ and fermions $hf\bar{f}$ in the general Higgs sector which contains higher isospin representations with arbitrary hypercharge. In Higgs…
The $SU(3)_C X SU(3)_L X U(1)_X$ gauge model with the minimal scalar sector (two Higgs triplets) is studied in detail. One of the vacuum expectation values $u$ is a source of lepton-number violations and a reason for the mixing among the…
We derive a general sum rule relating the Higgs coupling to W and Z bosons to the total cross section of longitudinal gauge boson scattering in I=0,1,2 isospin channels. The Higgs coupling larger than in the Standard Model implies…
As the Higgs boson properties settle, the constraints on the Standard Model extensions tighten. We consider all possible new fermions that can couple to the Higgs, inspecting sets of up to four chiral multiplets. We confront them with…
We build an supersymmetric version of the minimal 3-3-1 model with just two Higgs triplets using the superfield formalism. We study the mass spectrum of all particles in concordance with the experimental bounds. At the tree level, the…
Triple gauge boson couplings between Z, gamma and the W boson are determined by exploiting their impact on radiative corrections to fermion-pair production in e+e- interactions at centre-of-mass energies near the Z-pole. Recent values of…