We examine the possibility that the dark matter (DM) interpretation of the GeV scale Fermi gamma-ray excess at the Galactic center can be realized in a specific framework-secluded singlet fermionic dark matter model with small mixing between the dark and Standard Model sectors. Within this framework, it is shown that the DM annihilation into a bottom-quark pair, Higgs pair, and new scalar pair, shown to give good fits to the Fermi gamma-ray data in various model independent studies, can be successfully reproduced in our model. Moreover, unavoidable constraints from the antiproton ratio by PAMELA and AMS-02, the gamma-ray emission from the dwarf spheroidal galaxies by the Fermi-LAT, and the Higgs measurements by the LHC are also considered. Then, we find our best-fit parameters for the Fermi gamma-ray excess without conflicting other experimental and cosmological constraints if uncertainties on the DM density profile of the Milky Way Galaxy are taken into account. Successfully surviving parameters are benchmark points for future study on the collider signals.

• Received 2 February 2016

DOI:https://doi.org/10.1103/PhysRevD.93.075023