  We consider minimal effective interactions of the 750 GeV mass resonance
observed recently by ATLAS and CMS. Assuming a new scalar and gauge invariant
effective interactions leads to non-trivial two particle scattering amplitudes
with asymptotic gauge boson states. The longitudinally polarized $W\pm$ and $Z$
bosons interacting via dimension-five effective operators provide stringent
constraints on the validity of the effective model. The large width found by
ATLAS implying a bound of approximately 500 GeV already below the resonance,
turns this scenario unlikely. For production mainly in gluon fusion we get an
upper bound of $\sim 1.3$ TeV and strong limits on the masses of the underlying
vector-like fermions are given.
