Dynamical Electroweak Symmetry Breaking with a heavy fermion in light of recent LHC results

Abstract

The recent announcement of a discovery of a possible Higgs-like particle -its spin and parity is yet to be determined- at the LHC with a mass of 126 GeV necessitates a fresh look at the nature of the electroweak symmetry breaking, in particular if this newly-discovered particle will turn out to have the quantum numbers of a Standard Model Higgs boson. Even if it were a $0^{+}$ scalar with the properties expected for a SM Higgs boson, there is still the quintessential hierarchy problem that one has to deal with and which, by itself, suggests a new physics energy scale around 1 TeV. This article presents a mini-review of one possible scenario: The formation of a fermion-antifermion condensate coming from a very heavy fourth generation and carrying the quantum number of the the SM Higgs field and thus breaking the electroweak symmetry.

Comments: Invited Review: to appear in a special issue of Advances in High Energy Physics (AHEP) on Very Heavy Quarks at the LHC. 8 double-column pages. 5 figures