Can Zee-Babu model implemented with scalar dark matter explain both Fermi-LAT 130 GeV γ-ray excess and neutrino physics?

Seungwon Baek,Eibun Senaha,P Ko,Hiroshi Okada

doi:10.1007/jhep09(2014)153

Abstract

We extend the Zee-Babu model for the neutrino masses and mixings by first incorporating a scalar dark matter X with Z 2 symmetry and then X and a dark scalar φ with global U(1) symmetry. In the latter scenario the singly and doubly charged scalars that are new in the Zee-Babu model can explain the large annihilation cross section of a dark matter pair into two photons as hinted by the recent analysis of the Fermi γ-ray space telescope data. These new scalars can also enhance the B(H → γγ), as the recent LHC results may suggest. The dark matter relic density can be explained. The direct detection rate of the dark matter is predicted to be about one order of magnitude down from the current experimental bound in the first scenario.

Highlights

Since DM is electrically neutral, the pair annihilation process into photons occurs through loop-induced diagrams
In the first scenario we introduced a real scalar dark matter X with Z2 symmetry: X → −X
We have shown that the present constraint on the couplings λXk and λXh which mix the dark matter and charged Higgs is not so strong and they can enhance the annihilation cross section of XX → γγ large enough to accommodate the recent hint

Summary

The Z2 model

We implement the Zee-Babu model for radiative generation of neutrino masses and mixings, by including a real scalar DM X with Z2 symmetry X → −X. We included the interaction between the new charged scalar and the SM leptons that are allowed by gauge symmetry, and the new charged scalar bosons are not stable and cause no problem. The original Zee-Babu model was focused on the neutrino physics, and the operators of Higgs portal types were not discussed properly. It is clear that those Higgs portal operators we include in the 2nd line of (2.3) can enhance H → γγ, without touching any other decay rates of the SM Higgs boson, as long as h± and k±± are heavy enough that the SM Higgs decays into these new scalar bosons are kinematically forbidden

Constraints on the potential

Thermal relic density and direct detection rate

Conclusions

A One-loop β functions of the quartic couplings