A Three site Higgsless model

Abstract

We analyze the spectrum and properties of a highly deconstructed Higgsless model with only three sites. Such a model contains sufficient complexity to incorporate interesting physics issues related to fermion masses and electroweak observables, yet remains simple enough that it could be encoded in a Matrix Element Generator program for use with Monte Carlo simulations. The gauge sector of this model is equivalent to that of the Breaking Electroweak Symmetry Strongly (BESS) model; the new physics of interest here lies in the fermion sector. We analyze the form of the fermion Yukawa couplings required to produce the ideal fermion delocalization that causes tree-level precision electroweak corrections to vanish. We discuss the size of one-loop corrections to $b\ensuremath{\rightarrow}s\ensuremath{\gamma}$, the weak-isospin violating parameter $\ensuremath{\alpha}T$ and the decay $Z\ensuremath{\rightarrow}b\overline{b}$. We find that the new fermiophobic vector states (the analogs of the gauge-boson Kaluza-Klein modes in a continuum model) can be reasonably light, with a mass as low as 380 GeV, while the extra (approximately vectorial) quark and lepton states (the analogs of the fermion Kaluza-Klein modes) must be heavier than 1.8 TeV.