Di-Photon excess in the 2HDM: hasting towards the instability and the   non-perturbative regime
  We challenge the interpretation of the di-photon excess recently observed by both ATLAS and CMS in a two Higgs doublet framework. Due to the large enhancement necessary to obtain the observed di-photon signal, a large number of colored and charged vector-like fermions are called for. We find that even before the hypercharge gauge coupling becomes non perturbative, the one loop effects of these fermions abruptly drive the scalar potential to instability. 
Enrico Bertuzzo, Pedro A.N. Machado and Marco Taoso
hep-ph