Abstract
We discuss how to constrain two interesting models with new physics at the TeV scale. The first one is the Randall-Sundrum model with gauge fields in the bulk. We find, that in order to have successful electroweak symmetry breaking the wave-functions of the bulk gauge fields have to be varying, which introduces a large S and T parameter. This in turn implies that the mass scale of the KK gauge bosons must be so heavy that they would be onobservable at the LHC. The second one is the Dimopoulos-Kaplan model of electroweak symmetry breaking via the SU(3)×SU(2) ×U(1) gauge group. We again find that due to the mixing between the heavy and the light gauge bosons there would be large corrections to electroweak prescision measurements, and the model is so constrained that it would not be observable at the LHC.
