  We explore several perturbative scenarios in which the di-photon excess at
750 GeV can potentially be explained: a scalar singlet, a two Higgs doublet
model (2HDM), a 2HDM with an extra singlet, and the decays of heavier
resonances, both vector and scalar. We draw the following conclusions: (i) due
to gauge invariance a 750 GeV scalar singlet can accommodate the observed
excess more readily than a scalar SU(2)_L doublet; (ii) scalar singlet
production via gluon fusion is one option, however, vector boson fusion can
also provide a large enough rate, (iii) 2HDMs with an extra singlet and no
extra fermions can only give a signal in a severely tuned region of the
parameter space; (iv) decays of heavier resonances can give a large enough
di-photon signal at 750 GeV, while simultaneously explaining the absence of a
signal at 8 TeV.
