Electroweak symmetry breaking and extra dimensions Original Research Article

Electroweak symmetry can be naturally broken by observed quark and gauge fields in various extra-dimensional configurations. No new fundamental fields are required below the quantum gravitational scale (∼ 10–100 TeV). We examine schemes in which the QCD gauge group alone, in compact extra dimensions, forms a composite Higgs doublet out of (t,b)L and a linear combination of the Kaluza–Klein modes of tR. The effective theory at low energies is the Standard Model. The top-quark mass is controlled by the number of active tR Kaluza–Klein modes below the string scale, and is in agreement with experiment.