  As an alternative to the metastability of the electroweak vacuum, resulting
from perturbative calculations, one can consider a non-perturbative effective
potential which, as at the beginning of the Standard Model, is restricted to
the pure $\Phi^4$ sector yet consistent with the known analytical and numerical
studies. In this approach, where the electroweak vacuum is now the
lowest-energy state, besides the resonance of mass $m_h=$ 125 GeV defined by
the quadratic shape of the potential at its minimum, the Higgs field should
exhibit a second resonance with mass $(M_H)^{\rm Theor}=690\,(30)$ GeV
associated with the zero-point energy determining the potential depth. In spite
of its large mass, this resonance would couple to longitudinal $W$s with the
same typical strength as the low-mass state at 125 GeV and represent a
relatively narrow resonance, mainly produced at LHC by gluon-gluon fusion.
  In this Letter, we review LHC data suggesting a new resonance of mass
$(M_H)^{\rm EXP} \sim 682\,(10)$ GeV, with a statistical significance that is
far from negligible.
