相关论文: Limits on Non-Commuting Extended Technicolor
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…
Using precision electroweak data, we put limits on ``natural'' top-color assisted technicolor models. Generically the new $U(1)$ gauge bosons in these models must have masses larger than roughly 2 TeV, although in certain (seemingly…
A recent study by Randall and Sundrum shows that models of Extended Technicolor (ETC) have interesting implications on rare B decays. We extend their study to the decay B -> mu+ mu- X. ETC models with a GIM mechanism predict a decay rate…
An extended technicolor model is constructed. Quark and lepton masses, spontaneous CP violation, and precision electroweak measurements are discussed. Dynamical symmetry breaking is analyzed using the concept of the BIG MAC.
Many types of physics beyond the standard model include an extended electroweak gauge group. If these extensions are associated with flavor symmetry breaking, the gauge interactions will not be flavor-universal. In this note we update the…
We discuss electroweak constraints on TeV scale extensions of the standard model. To obtain model-independent results, effective theory approach is adopted. Constraints are given on arbitrary linear combinations of a set of dimension-6…
In this lecture I give an introduction to technicolor and extended technicolor theories. I discuss the issues models of dynamical electroweak symmetry breaking struggle with and propose how non QCD-like dynamics, such as a `walking' or…
We review some recent results on models of dynamical electroweak symmetry breaking involving extended technicolor.
It is well known that technicolor models in which the electroweak symmetry is broken by QCD-like strong dynamics at the TeV scale generally predict unacceptably large corrections to low-energy observables. We investigate the models of…
Extended technicolor (ETC) theories typically require ETC gauge bosons lighter than of order 1 TeV, to perturbatively generate the $t$ quark mass. We point out that explicit models of $t-b$ mass splitting also typically contain additional…
Dynamical breaking of the electroweak theory, i.e. technicolor, is an intriguing extension of the Standard Model. Recently new models have been proposed featuring walking dynamics for a very low number of techniflavors. These technicolor…
We compute the bounds from precision observables on alternative theories of electroweak symmetry breaking. We show that a cut-off as large as 3 TeV can be accomodated by the present data, without unnatural fine tuning.
We study a model in which the electroweak symmetry is dynamically broken by technicolor interactions and the symmetry-breaking is communicated to the quarks and leptons by a weak doublet of scalar fields. The scalars may be regarded as…
There are quasi-conformal theories, like the Minimal and Ultraminimal Technicolor models, which may break dynamically the gauge symmetry of the Standard Model and at the same time are compatible with electroweak precision data. The main…
We study technicolor models in which all of the technifermions are color-singlets, focusing on the case in these fermions transform according to the fundamental representation of the technicolor gauge group. Our analysis includes a…
Collider measurements on electroweak physics are summarised. Although the precision on some observables is very high, no deviation from the Standard Model of electroweak interactions is observed. The data allow to set stringent limits on…
The motivations for studying dynamical scenarios of electroweak and flavor symmetry breaking are reviewed and the latest ideas, especially topcolor-assisted technicolor, are summarized. Several technicolor signatures at the Tevatron and…
LEP precision measurements of the $Zb\bar{b}$ vertex coupling are sufficiently accurate to see the non-oblique corrections from the heavy gauge boson responsible for the large top mass in standard extended tecnicolour models. If the ETC…
We revisit the global fit to electroweak precision observables in the Standard Model and present model-independent bounds on several general new physics scenarios. We present a projection of the fit based on the expected experimental…
We review the connection between $m_t$ and the $Zb\bar b$ vertex in ETC models and demonstrate the power of the resulting experimental constraint on models with weak-singlet ETC bosons. Some efforts to bring ETC models into agreement with…