Warped Higgsless Models with IR--Brane Kinetic Terms

We examine a warped higgsless SU(2)L × SU(2)R × U(1)B−L model in 5-d with IR(TeV)-brane kinetic terms. It is shown that adding a brane term for the U(1)B−L gauge field does not affect the scale ( ~ 2–3 TeV) where perturbative unitarity in WL+WL−→WL+WL− is violated. This term could, however, enhance the agreement of the model with the precision electroweak data. In contrast, the inclusion of a kinetic term corresponding to the SU(2)D custodial symmetry of the theory delays the unitarity violation in WL± scattering to energy scales of ~ 6–7 TeV for a significant fraction of the parameter space. This is about a factor of 4 improvement compared to the corresponding scale of unitarity violation in the Standard Model without a Higgs. We also show that null searches for extra gauge bosons at the Tevatron and for contact interactions at LEP II place non-trivial bounds on the size of the IR-brane terms.