Related papers: The Effects on $S$, $T$, and $U$ from Higher-Dimen…
We analyze the corrections to the precision EW observables in minimal composite Higgs models by using a general effective parametrization which also includes the lightest fermionic resonances. A new, possibly large, logarithmically…
It is shown that the gauge fixings of the Z and the W fields and three scalars are via nonconserved axial-vector and charged vector currents of massive fermions dynamically generated by fermion masses in the SM of EW interactions. The top…
Electroweak precision observables are fundamentally important for testing the standard model (SM) or its extensions. The influences to observables from new physics within the electroweak sector can be expressed in terms of oblique…
We study the properties of heavy fermions in the vector-like representation of the electro-weak gauge group $SU(2)_W\times U(1)_Y$ with Yukawa couplings to the standard model Higgs boson. Applying the renormalization group analysis, we…
The existence of mirror fermions interacting strongly under a new gauge group and having masses near the electroweak scale has been recently proposed as a viable alternative to the standard-model Higgs mechanism. The main purpose of this…
We discuss the electroweak gauge symmetry breaking triggered by a new strong attractive interaction to condensate fermion-antifermion, and topcolor is a prototype. To deal with the fermion pairing, a general method based on the…
Perturbing the standard Gross-Neveu model for $N^3$ fermions by quartic interactions with the appropriate tensorial contraction patterns, we reduce the original $U(N^3)$ symmetry to either $U(N)\times U(N^2)$ or $U(N)\times U(N)\times…
We discuss ideal delocalization of fermions in a bulk SU(2) x SU(2) x U(1) Higgsless model with a flat or warped extra dimension. So as to make an extra dimensional interpretation possible, both the weak and hypercharge properties of the…
The existence of extra chiral generations with all fermions heavier than M_Z is strongly disfavoured by the precision electroweak data. However the data are fitted nicely even by a few extra generations, if one allows neutral leptons to…
The complete one-loop radiative corrections to third generation scalar fermions into gauge bosons Z and W^\pm is considered. We focus on \wt{f}_2 \to Z \wt{f}_1 and \wt{f}_i \to W^\pm \wt{f'}_j (f,f'=t,b). We include both SUSY-QCD, QED and…
The recent measurement by the CDF Collaboration of the $W$ boson mass is in significant tension with the Standard Model expectation, showing a discrepancy of seven standard deviations. A larger value of $m_W$ affects the global electroweak…
Experiment shows that the top quark is far heavier than the other elementary fermions. This finding has stimulated research on theories of electroweak and flavor symmetry breaking that include physics beyond the standard model. Efforts to…
The main challenge faced by Higgsless models of electroweak symmetry breaking is to reconcile the experimental constraints imposed by the precision electroweak data and the top quark phenomenology with the unitarity constraints imposed by…
The Twin Higgs model is the preeminent example of a theory of neutral naturalness, where the new particles that alleviate the little hierarchy problem are Standard Model (SM) singlets. The most promising collider search strategy, based on…
The CDF collaboration recently reported a new precise measurement of the $W$ boson mass $M_W$ with a central value significantly larger than the SM prediction. We explore the effects of including this new measurement on a fit of the…
We complete the analysis of the effective field theory at the electroweak scale for minimal models of fundamental partial compositeness. Specifically, we consider fermions in the complex and real representation of the gauge group underlying…
We study the dynamics of chiral SU(N) gauge theories. These contain Weyl fermions in the symmetric or anti-symmetric representation of the gauge group, together with further fermions in the fundamental and anti-fundamental. We revisit an…
The Standard Model (SM) is a chiral theory, where right- and left-handed fermion fields transform differently under the gauge group. Extra fermions, if they do exist, need to be heavy otherwise they would have already been observed. With no…
We study the evolution of an asymptotically free vectorial SU($N$) gauge theory from the ultraviolet to the infrared and the resultant phase structure in the general case in which the theory contains fermions transforming according to…
We consider models that generate hierarchies via the separation of fermion wavefunctions in higher-dimensional spaces. We calculate the effects of gauge interactions between fermions and show that these are important and could help to…