Generational Structure of Models with Dynamical Symmetry Breaking

Thomas Ryttov, Robert Shrock

Research output: Contribution to journalJournal articleResearchpeer-review


In models with dynamical electroweak symmetry breaking, this breaking is normally communicated to quarks and leptons by a set of vector bosons with masses generated via sequential breaking of a larger gauge symmetry. In reasonably ultraviolet-complete theories of this type, the number of stages of breaking of the larger gauge symmetry is usually equal to the observed number of quark and lepton generations, $N_{gen.}=3$. Here we investigate the general question of how the construction and properties of these models depend on $N_{gen.}$, regarded as a variable. We build and analyze models with illustrative values of $N_{gen.}$ different from 3 (namely, $N_{gen.}=1,2,4$) that exhibit the necessary sequential symmetry breaking down to a strongly coupled sector that dynamically breaks electroweak symmetry. Our results for variable $N_{gen.}$ show that one can robustly obtain, for this latter sector, a theory with a gauge coupling that is large but slowly running, controlled by an approximate infrared fixed point of the renormalization group. Owing to this, we find that for all of the values of $N_{gen.}$ considered, standard-model fermions of the highest generation have masses that can be comparable to the electroweak-symmetry breaking scale. We also study the interplay of multiple strongly coupled gauge symmetries in these models.
Translated title of the contributionGenerational Structure of Models with Dynamical Symmetry Breaking
Original languageEnglish
JournalPhysical Review D
Publication statusPublished - 12. Apr 2010
Externally publishedYes


  • hep-ph

Cite this