Z′production at the LHC in the four-site Higgsless model

Abstract

We study the phenomenology of the neutral gauge sector of the four-site Higgsless model, based on the $SU(2{)}_{L}\ifmmode\times\else\texttimes\fi{}SU(2{)}_{1}\ifmmode\times\else\texttimes\fi{}SU(2{)}_{2}\ifmmode\times\else\texttimes\fi{}U(1{)}_{Y}$ gauge symmetry, at present colliders. The model predicts the existence of two neutral and four charged extra gauge bosons, ${Z}_{1,2}$ and ${W}_{1,2}^{\ifmmode\pm\else\textpm\fi{}}$. We expand and update a previous study, by concentrating on the neutral sector. We derive new limits on ${Z}_{1,2}$-boson masses and couplings from recent direct searches at the Tevatron. We moreover estimate the discovery potential at the Tevatron with a project luminosity $L=10\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$, and at the 7 TeV LHC with $L=1\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. In contrast to other Higgsless theories characterized by almost fermiophobic extra gauge bosons, the four-site model allows sizable ${Z}_{1,2}$-boson couplings to standard model fermions. Owing to this feature, we find that in the next 2 years the extra ${Z}_{1,2}$ bosons could be discovered in the favored Drell-Yan channel at the 7 TeV LHC for ${Z}_{1,2}$ masses in the TeV region, depending on model parameters.