Diphoton excess and VV-scattering

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 nontrivial two-particle scattering amplitudes with asymptotic gauge boson states. The longitudinally polarized W± 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 ∼ 1.3 TeV and strong limits on the masses of the underlying vector-like fermions are given.