Electroweak symmetry breaking as a consequence of compact dimensions
  It has been shown recently that the Higgs doublet may be composite, with the left-handed top-bottom doublet and a new right-handed anti-quark as constituents bound by some four-quark operators with nonperturbative coefficients. I show that these operators are naturally induced if there are extra space dimensions with a compactification scale in the multi-TeV range. The Higgs compositness is due mainly to the Kaluza-Klein modes of the gluons, while flavor symmetry breaking may be provided by various fields propagating in the compact dimensions. I comment briefly on the embedding of this scenario in string theory. 
Bogdan A. Dobrescu