Related papers: The Effects on $S$, $T$, and $U$ from Higher-Dimen…
We discuss the selection of fermion representations in technicolor models with a view toward minimizing technicolor contributions to the precision electroweak $S$ parameter. We present and analyze models that involve one technifermion…
We calculate the oblique electroweak corrections and confront with the experiments in an extension of the Standard Model. The new fields added are a vector-like weak doublet and a singlet fermion. After electroweak symmetry breaking there…
We calculate the oblique electroweak corrections and confront them with the experiments in a composite Higgs version of the standard model. A vector-like weak doublet and a singlet fermion are added to the standard model without elementary…
We study the effect of bulk fermions on electroweak precision observables in a recently proposed model with warped extra dimensions and no custodial symmetry. We find that the top-quark mass, together with the corrections to the Zbb vertex…
We compute the six oblique parameters $S, T, U, V, W, X$ in a New Physics Model with an arbitrary number of new fermions, in arbitrary representations of $SU(2) \times U(1)$, and mixing arbitrarily among themselves. We show that $S$ and $U$…
The contributions to $S$, $T$, and $U$ from heavy scalars in any irreducible representation of the electroweak gauge group $SU(2)_L\times U(1)_Y$ are obtained. We find that in the case of a heavy scalar doublet there is a slight difference…
The S,T, and U formalism for studying electroweak precision data has recently been updated to include the effects of new light physics and within this analysis the latest LEP and SLC data tightly constrain models of physics beyond the…
SU(3) gauge theory with eight massless fundamental fermions seems to be near the conformal boundary, and is a candidate theory of walking technicolor. Along the series of study by LatKMI collaboration using HISQ fermions, S-parameter and…
We calculate the ultraviolet to infrared evolution and analyze possible types of infrared behavior for several asymptotically free chiral gauge theories with gauge group SU($N$) and massless chiral fermions transforming according to a…
We propose a supersymmetric technicolor model in which the electroweak symmetry breaking is communicated to the quarks and leptons by technicolored $SU(2)_W$-singlet scalars. When the technifermions condense, the quarks and leptons of the…
We propose a mechanism which can reduce the Peskin and Takeuchi's S, T and U parameters in dynamical electroweak symmetry breaking models. It is interesting that not only S but also T parameter can become small even if there exists large…
We investigate the conformal window of four-dimensional gauge theories with fermionic matter fields in multiple representations. Of particularly relevant examples are the ultra-violet complete models with fermions in two distinct…
Extra-dimensional Higgsless models with electroweak symmetry breaking through boundary conditions generically have difficulties with electroweak precision constraints, when the fermions are localized to the ``branes'' in the fifth…
We consider various constraints on Higgsless models of electroweak symmetry breaking based on a bulk SU(2)_L x SU(2)_R x U(1)_{B-L} gauge group in warped space. First we show that the S parameter which is positive if fermions are localized…
We study the ultraviolet to infrared evolution and nonperturbative behavior of a simple set of asymptotically free chiral gauge theories with an SU($N$) gauge group and an anomaly-free set of $n_{S_k}$ copies of chiral fermions transforming…
We look for UV fixed points of non-abelian $SU(n_c)$ gauge theories in $4+2\epsilon$ dimensions with $n_f$ Dirac fermions in the fundamental representation, using the available five-loop $\overline{{\rm MS}}$ $\beta$-function and employing…
Within the framework of a general non-linear effective field theory describing the electroweak symmetry breaking, we perform a detailed analysis of the next-to-leading contributions to the electroweak oblique parameters $S$ and $T$ from…
The interplay of deconfinement and chiral symmetry restoration are considered in terms of effective theories. We generalize the earlier model studies by considering fermions in higher representations, and study the finite temperature phase…
We show that the S parameter is not finite in theories of electroweak symmetry breaking in a slice of anti--de Sitter five-dimensional space, with the light fermions localized in the ultraviolet. We compute the one-loop contributions to S…
Precision electroweak measurements have been claimed to eliminate almost all models of technicolor. We show that the assumptions made to calculate the oblique parameters $S$,$T$,$U$ apply to QCD--like technicolor models which were ruled out…