SIGNATURES of DYNAMICAL SYMMETRY BREAKING at TEVATRON UPGRADE and LHC

We present some results on the usefulness of upgraded Tevatron and LHC hadron colliders to test the idea of a strongly interacting sector as responsible for the electroweak symmetry breaking. The calculations are performed within an effective lagrangian description, called the BESS model 1 (BESS standing for Breaking Electroweak Symmetry Strongly), which provides for a rather general frame based on the standing point of custodial symmetry and gauge invariance, without specifying any dynamical scheme. We are interested in studying a spontaneous symmetry breaking avoiding physical scalar particles. An effective lagrangian describing in an unified way mass terms and interactions of the standard electroweak gauge bosons can be derived as a gauged non linear σ-model. Using extensively the fact that any non linear σ-model is gauge equivalent to theories with additional hidden local symmetry , we introduce new vector resonances, similar to ordinary ρ vector mesons or to the techni-ρ particle of technicolor theories, as the gauge bosons associated to the hidden symmetry group of SU(2) type. Under the assumption they are dynamical, we will get the SU(2) minimal BESS model 1 described by a Yang Mills lagrangian whose gauge group is SU(2)L ⊗U(1)Y ⊗ SU(2)V . The parameters it contains, besides the standard model (hereafter denoted as SM) ones, are the mass MV of the new bosons forming a degenerate SU(2) triplet and their gauge coupling constant g. The new particles are naturally coupled to fermions through mixing between W , Y and V , although a direct coupling, specified by a new parameter b, is possible. The SM is recovered in the limit g → ∞ and b = 0. Mixings of the ordinary gauge bosons to the V ’s are O (g/g). Due to these mixings, the V bosons are coupled to fermions even for b = 0. Furthermore these couplings are still