Aspects of dynamical electroweak symmetry breaking

Limits on noncommuting extended technicolor

“…In strong-ETC theories [16], g 2 is the product of the scalar couplings to the top quark and the technifermions and M is the mass of the light composite scalar [10]. In the context of these theories, the "accuracy" with which the ETC gauge coupling must be adjusted is approximately equal to the ratio of M 2 /g 2 to its naive value, f 2 /4.…”

“…models in which the ETC coupling is fine-tuned to be close to the critical value necessary for the ETC interactions to produce chiral symmetry breaking, the LRinteractions become enhanced. Physically, this is due to the presence of a composite scalar [10] which is light compared to f and communicates electroweak symmetry breaking to the top quark. Whether or not the ETC interactions are strong, we can write the top quark mass as [7] 4) where the numerator contains an estimate of the technifermion condensate (using dimensional analysis [9]), and f Q is the Goldstone boson decay constant associated with the technifermions which feed down a mass to the top quark.…”

Chiral hierarchies, compositeness, and the renormalization group

“…It transforms in the (N f , N f ) representation of the chiral symmetry group. If a large hierarchy between v and the scale Λ of new physics is to be established in a consistent way, the chiral symmetry breaking phase transition must be of second order in the couplings of the high-energy theory [19]. Hence the low-energy dynamics of the composite Higgs field Σ and the fermions Ψ j can be described by an effective Ginsburg-Landau Lagrange density of the form…”

Holographic bosonic technicolor

“…It has been known for some time that models with strongly-coupled extended technicolor sectors can produce exactly this low-energy particle spectrum [27]. We have presented a holographic representation of a strongly-coupled ETC theory in which low energy properties of the theory are calculable.…”