Related papers: Non--decoupling, triviality and the $\rho$ paramet…
The contribution to the $\rho$--parameter of the quark--Higgs sector of the supersymmetric standard model is computed non--perturbatively using the large--$\nf$ expansion for the case tan$\beta$=0. An explicit formula is found for the…
We compute some non--decoupling effects in the standard model, such as the $\rho$ parameter, to all orders in the coupling constant expansion. We analyze their large order behavior and explicitly show how it is related to the…
We investigate, using a $1/N$ expansion, the behavior of a parameter in the scalar--fermion sector of the standard model that shows perturbative non--decoupling as the fermion becomes heavy. This low energy parameter is related to the $S$…
We perform an all-order calculation of the \rho parameter in a simplified framework, where the top propagator can be calculated exactly. Special emphasis is placed on the question of gauge invariance and the treatment of non-perturbative…
We calculate the triviality bound on the Higgs mass in scalar field theory models whose global symmetry group $SU(2)_L \times SU(2)_{\rm custodial} \approx O(4)$ has been replaced by $O(N)$ and $N$ has been taken to infinity. Limits on…
The scalar sector of the Standard Model is extended to include an arbitrary assortment of scalars. In the case where this assignment does not preserve $\rho=1$ at the tree-level, the departure from unity itself puts the most stringent…
Using the classical recursion relations we compute scattering amplitudes in a spontaneously broken Gauge-Higgs theory into final states involving high multiplicities of massive vector bosons and Higgs bosons. These amplitudes are computed…
A brief review of the role of the Higgs mechanism and the ensuing Higgs particle in the Minimal Standard Model is given. Then the property of triviality of the scalar sector in the Minimal Standard Model and the upper bound on the Higgs…
The triviality of the scalar sector of the standard one-doublet Higgs model implies that this model is only an effective low-energy theory valid below some cut-off scale Lambda. For a heavy higgs this scale must be relatively low (10 TeV or…
We show in this paper that the 1/N expansion is a reliable tool to calculate the properties of a heavy Higgs boson. The 1/N expansion sums up all orders in perturbation theory, and therefore avoids the renormalization scheme dependence of…
A large hierarchy between the electroweak scale and virtually any new scale of beyond-Standard-Model physics is often claimed to be unnatural. Sometimes, the apparent disparity between the measured Higgs mass and the size of the typical…
Using the hierarchical approximation, we discuss the cut-off dependence of the renormalized quantities of a scalar field theory. The naturalness problem and questions related to triviality bounds are briefly discussed. We discuss unphysical…
While supersymmetric extensions of the Standard Model can be fully described in terms of explicitly broken global supersymmetry, this description is only effective. Once related to spontaneous breaking in a more fundamental theory, the…
Present data, both from direct Higgs search and from analysis of electroweak data, are starting to become rather restrictive on the possible values for the mass of the standard model Higgs. We discuss a new physics scenario based on a model…
We introduce N-parameter perturbation theory as a new tool for the study of non-linear relativistic phenomena. The main ingredient in this formulation is the use of the Baker-Campbell-Hausdorff formula. The associated machinery allows us to…
We discuss the current picture of the standard model's scalar sector at strong coupling. We compare the pattern observed in the scalar sector in perturbation theory up to two-loop with the nonperturbative solution obtained by a…
We simulate a theory with $N_f=2$ heavy quarks of mass $M$. At energies much smaller than $M$ the heavy quarks decouple and the theory can be described by an effective theory which is a pure gauge theory to leading order in $1/M$. We…
In the standard model (SM), the $\rho$ parameter is equal to 1 and the ratio $\lambda_{WZ}$ of Higgs $\to ZZ$ and Higgs $\to WW$ is also equal to 1 at the tree level. When going beyond the SM with more than one types of Higgs…
A cutoff version of the $\lambda \phi^4$ O(N) model is considered to leading order in 1/N with particular attention to the effective potential, which is surprisingly rich in structure. With suitable restriction on a background classical…
We compute the large-$m_t$ contributions to the $Zb\overline b$ vertex in the Standard Model non-perturbatively using both the $1/\nc$ and the $1/\nf$ expansions. Triviality and its consequences for the perturbative result are…