HIGGSLESS MODELS and DECONSTRUCTION

摘要

We give a brief review on the deconstructed Higgsless models (linear moosemodels). The Fermi-constant G_Fand the low energy ρparameter are evaluated,and the physics behind the delay of unitarity violation is clarified. In order toconstruct a viable model consistent with the precision electroweak data, left-handed quarks and leptons need to be delocalized over the deconstructed extradimension. We discuss "ideal delocalization" of quarks and leptons with whichdeviations in precision electroweak parameters are minimized. As contributionsto the S parameter vanish to leading order with the ideal delocalization, currentconstraints on these models arise from limits on deviations in triple gauge bosonvertices. By using the block-spin transformation, we argue that low energyeffective theory of any consistent Higgsless model can be described by highlydeconstructed linear moose model with only a fewer number of deconstructedsites. We propose the three-site model as the lowest order effective theory ofHiggsless models.