130 GeV gamma-ray line and enhancement of h → γγ in the Higgs triplet model plus a scalar dark matter

With a discrete Z(2) symmetry being imposed, we introduce a real singlet scalar S to the Higgs triplet model with the motivation of explaining the tentative evidence for a line spectral feature at E-gamma = 130 GeV in the Fermi Large Area Telescope data. The model can naturally satisfy the experimental constraints of the dark matter relic density and direct detection data from Xenon100. The doubly charged and single charged scalars can enhance the annihilation cross section of SS -> gamma gamma via the one-loop contributions and give negligible contributions to the relic density. (SS ->gamma gamma) for m(S) = 130 GeV can reach O(1) X 10(-27) cm(3) s(-1) for the small charged scalars' masses and the coupling constant that is larger than 1. Also, this model predicts a second photon peak at 114 GeV from the annihilation SS -> gamma Z, and the cross section is approximately 0.76 times that of SS -> gamma gamma, which is below the upper limit reported by Fermi Large Area Telescope. Finally, the light charged scalars can enhance the LHC diphoton Higgs rate and make it consistent with the experimental data reported by ATLAS and CMS. DOI: 10.1103/PhysRevD.87.015015