(Not) Summing over Kaluza-Kleins

Models in extra-dimensions have unique features. Many of their surprising properties simply result from the underlying 5D structure. This structure shows up as ``Sum Rules'' involving the whole tower of Kaluza-Kleins. In this paper, we present a holographic shortcut and derive these results without solving the eigenvalue problem: we express 4D physical quantities directly in terms of the 5D metric. In warped space, one can go further and isolate the effect of the new physics sector. This method can be used for any 5D model, and we apply it here to the case of holographic QCD and technicolor

The role of spurions in Higgs-less electroweak effective theories

Inspired by recent developments of moose models we reconsider low-energy effective theories of Goldstone bosons, gauge fields and chiral fermions applied to low-energy QCD and to Higgs-less electroweak symmetry breaking. Couplings and the corresponding reduction of symmetry are introduced via constraints enforced by a set of non-propagating covariantly constant spurion fields. Relics of the latter are used as small expansion parameters conjointly with the usual low-energy expansion. Certain couplings can only appear at higher orders of the spurion expansion and consequently, they become naturally suppressed independently of the idea of dimensional deconstruction. At leading order this leads to a set of generalized Weinberg sum rules and to the suppression of non-standard couplings to fermions in Higgs-less EWSB models with the minimal particle content. Within the latter, higher spurion terms allow for a fermion mass matrix with the standard CKM structure and CP violation. In addition, Majorana masses for neutrinos are possible. Examples of non-minimal models are briefly mentioned.Comment: Some precisions added to section 3.4. Reference [13] added. To appear in EPJ

Chiral Dynamics beyond the Standard Model

The SM Lagrangian without physical scalars is rewritten as the LO of a Low-Energy Effective Theory invariant under a higher non linear symmetry S_{nat} \supset SU(2)_W \times U(1)_Y. Soft breaking of S_{nat} defines a hierarchy of non standard effects dominated by universal couplings of right-handed quarks to W. The interface of corresponding EW tests with non perturbative QCD aspects is briefly discussed.Comment: 6 pages, Tallk given at QCD06 Conference, Montpellier, France, 3-7 July 2006, to appear in the Proceeding