arXiv:1001.2716v1 [hep-ph] 15 Jan 2010 From hidden symmetry to extra dimensions: a five dimensional formulation of the Degenerate BESS model Francesco Coradeschi, Stefania De Curtis and Daniele Dominici Department of Physics, University of Florence, and INFN, Via Sansone 1, 50019 Sesto F., (FI), Italy (Dated: December 15, 2018) We consider the continuum limit of a moose model corresponding to a generalization to N sites of the Degenerate BESS model. The five dimensional formulation emerging in this limit is a realization of a RS1 type model with SU (2)$_{L}$ ⊗ SU (2)$_{R}$ in the bulk, broken by boundary conditions and a vacuum expectation value on the infrared brane. A low energy effective Lagrangian is derived by means of the holographic technique and corresponding bounds on the model parameters are obtained. The exact nature of the mechanism that leads to the breakdown of the electroweak (EW) symmetry is one of the relevant open questions in particle physics. While waiting for the first experimental data from the Large Hadron Collider, it is worthwhile to explore the potential electroweak breaking scenarios from a theoretical point of view. In the Standard Model (SM), the mechanism of the EW symmetry breaking implies the presence a fundamental scalar particle, the Higgs boson, with a light mass as suggested by EW fits. However, this mechanism is affected by a serious fine-tuning problem, the hierarchy problem, because the mass of the Higgs boson is not protected against radiative corrections and would naturally be expected to be as large as the physical UV cut-off of the SM, which could be as high as M$_{P}$ ≃ 10 19 GeV. Possible solutions to the hierarchy problem are the technicolor (TC) theories [1–3] (that postulate the presence of new strong interactions around the TeV scale) and extra- dimensional theories [4–6]. These seemingly unrelated classes of theories have in fact a profound connection through the AdS/CFT correspondence [7]. According to this conjec- ture, five dimensional (5D) models on AdS space are “holographic duals” to 4D theories with spontaneously broken conformal invariance. The duality means that when the 5D theory is I. INTRODUCTION