2Laboratoire de Physique des Hautes Energies et Astrophysique

We study the two photon decay channel of the Standard Model-like component of the CP-even Higgs bosons present in the type II Seesaw Model. The corresponding cross-section is found to be signifi-cantly enhanced in parts of the parameter space, due to the (doubly-)charged Higgs bosons ’ (H±±)H ± virtual contributions, while all the other Higgs decay channels remain Standard Model(SM)-like. In other parts of the parameter space H± ± (and H±) interfere destructively, reducing the two photon branching ratio tremendously below the SM prediction. Such properties allow to account for any excess such as the one reported by ATLAS/CMS at ≈ 125 GeV if confirmed by fu-ture data; if not, for the fact that a SM-like Higgs exclusion in the diphoton channel around 114–115 GeV as reported by ATLAS, does not contradict a SM-like Higgs at LEP(!), and at any rate, for the fact that ATLAS/CMS exclusion limits put stringent lower bounds on the H± ± mass, particularly in the parameter space regions where the direct limits from same-sign leptonic decays of H± ± do not apply. ∗corresponding author a