Gauge theories on an interval: Unitarity without a Higgs boson
Abstract
We consider extra dimensional gauge theories on an interval. We first review the derivation of the consistent boundary conditions (BC’s) from the action principle. These BC’s include choices that give rise to the breaking of the gauge symmetries. The boundary conditions could be chosen to coincide with those commonly applied in orbifold theories, but there are many more possibilities. To investigate the nature of gauge symmetry breaking via BC’s we calculate the elastic scattering amplitudes for longitudinal gauge bosons. We find that using a consistent set of BC’s the terms in these amplitudes that explicitly grow with energy always cancel without having to introduce any additional scalar degree of freedom, but rather by the exchange of KaluzaKlein (KK) gauge bosons. This suggests that perhaps the standard model Higgs boson could be completely eliminated in favor of some KK towers of gauge fields. We show that from the lowenergy effective theory perspective this seems to be indeed possible. We display an extra dimensional toy model, where BC’s introduce a symmetry breaking pattern and mass spectrum that resembles that in the standard model.
 Publication:

Physical Review D
 Pub Date:
 March 2004
 DOI:
 10.1103/PhysRevD.69.055006
 arXiv:
 arXiv:hepph/0305237
 Bibcode:
 2004PhRvD..69e5006C
 Keywords:

 12.60.Cn;
 11.10.Kk;
 11.15.Ex;
 12.10.Kt;
 Extensions of electroweak gauge sector;
 Field theories in dimensions other than four;
 Spontaneous breaking of gauge symmetries;
 Unification of couplings;
 mass relations;
 High Energy Physics  Phenomenology;
 High Energy Physics  Theory
 EPrint:
 33 pages, 3 figures included