LOW-ENERGY STRONG ELECTROWEAK SECTOR WITH DECOUPLING

We discuss possible symmetries of effective theories describing spinle ss and spin-1 bosons, mainly to concentrate on an intriguing phenomeno logical possibility: that of a hardly noticeable strong electroweak se ctor al relatively low energies. Specifically, a model with both vecto r and axial vector strong interacting bosons may possess a discrete sy mmetry imposing degeneracy of the two sets of bosons (degenerate BESS model). in such, a case its effects at low energies become almost invi sible and the mode: easily passes al::ow energy precision tests. The r eason. lies essentially in the fact that the mode: automatically satis fies decoupling, contrary to models with only vectors. For large mass of the degenerate spin-one bosons the model becomes identical at the c lassical level to the standard model taken, in the limit of infinite H iggs boson mass. For these reasons we have thought ii worthwhile to fu lly develop the model, together with its possible generalizations, and to study the expected phenomenology. For instance, just because of it s invisibility at low energy, it is conceivable that degenerate BESS h as low mass spin-one states and giver, quite visible signals a: existi ng a; forthcoming accelerators.