Oblique corrections from Higgsless models in warped space

Abstract

We calculate the tree-level oblique corrections to electroweak precision observables generated in Higgless models of electroweak symmetry breaking with a 5D $\mathrm{S}\mathrm{U}(2{)}_{L}\ifmmode\times\else\texttimes\fi{}\mathrm{S}\mathrm{U}(2{)}_{R}\ifmmode\times\else\texttimes\fi{}\mathrm{U}(1{)}_{B\ensuremath{-}L}$ gauge group on a warped background. In the absence of brane induced kinetic terms (and equal left and right gauge couplings) we find the $S$ parameter to be $\ensuremath{\sim}1.15$, while $T\ensuremath{\sim}U\ensuremath{\sim}0$, as in technicolor theories. Planck brane induced kinetic terms and unequal left-right couplings can lower $S$, however for sufficiently low values of $S$ tree-level unitarity will be lost. A kinetic term localized on the TeV brane for $\mathrm{S}\mathrm{U}(2{)}_{D}$ will generically increase $S$, however an induced kinetic term for $\mathrm{U}(1{)}_{B\ensuremath{-}L}$ on the TeV brane will lower $S$. With an appropriate choice of the value of this induced kinetic term $S\ensuremath{\sim}0$ can be achieved. In this case the mass of the lowest ${Z}^{\ensuremath{'}}$ mode will be lowered to about 300 GeV.