  The existence of a new strong interacting sector around E ~ 1 TeV is a common
feature of Higgsless electroweak theories but also of theories with a light
Higgs, for instance, when this is not elementary. In those schemes, this new
interaction could be at the origin of an extended spectra with, in particular,
spin-1 resonances that could be hinted in elastic gauge boson scattering.
Information on those resonances, if they exist, must be contained in the
low-energy couplings of the electroweak chiral effective theory. Using the
facts that: i) the scattering of longitudinal gauge bosons, W_L, Z_L, can be
well described in the high-energy region (E >> M_W) by the scattering of the
corresponding Goldstone bosons (equivalence theorem) and that ii) the zeros of
the scattering amplitude carry the information on the heavier spectrum that has
been integrated out; we employ the O(p^4) electroweak chiral Lagrangian, with
or without a light Higgs state to identify the parameter space region of the
low-energy couplings where vector resonances may arise.
