Physical Review D
LHC has reported tantalizing hints for a Higgs boson of mass 125 GeV decaying into two photons. We focus on two-Higgs-doublet Models, and study the interesting possibility that the heavier scalar H has been seen, with the lightest scalar h having thus far escaped detection. Nonobservation of h at LEP severely constrains the parameter-space of two-Higgs-doublet models. We analyze cases where the decay H -> hh is kinematically allowed, and cases where it is not, in the context of type I, type II, lepton-specific, and flipped models.
Ferreira, P. M., Santos, R., Sher, M., & Silva, J. P. (2012). Could the LHC two-photon signal correspond to the heavier scalar in two-Higgs-doublet models?. Physical Review D, 85(3), 035020.