New Physics at 1 TeV?

If decays of a heavy particle $S$ are responsible for the diphoton excess with invariant mass $750$ GeV observed at the $13$ TeV LHC run, it can be easily accomodated in the Standard Model. Two scenarios are considered: production in gluon fusion through a loop of heavy isosinglet quark(s) and production in photon fusion through a loop of heavy isosinglet leptons. In the second case many heavy leptons are needed or/and they should have large electric charges in order to reproduce experimental data on $\sigma_{pp \to SX} \cdot \text{Br}(S \to \gamma \gamma)$.