Interpretation of the Galactic gamma-ray excess with the dark matter indicated by ${}^8$Be and ${}^4$He anomalous transitions

Abstract

The long-standing Galactic center gamma-ray excess could be explained by GeV dark matter (DM) annihilation, while the DM interpretation seems in tension with recent joint limits from different astronomical scale observations, such as dwarf spheroidal galaxies, the Milky Way halo and galaxy groups/clusters. Motivated by ${}^8$Be and ${}^4$He anomalous transitions with possible new interactions mediated by a vector boson $X$, we consider a small fraction of DM mainly annihilating into a pair of on-shell vector boson $XX$ followed by $X\to e^{+}{e}^{-}$ in this paper. The Galactic center gamma-ray excess is explained by this DM cascade annihilation. The gamma rays are mainly from Inverse Compton Scattering emission, and the DM cascade annihilation could be compatible with joint astrophysical limits and meanwhile be allowed by the AMS-02 positron observation. The direct detection of this model is also discussed.

16 pages, 3 figures. Version accepted by CPC

References in corpus (24)

• Results from a search for dark matter in the complete LUX exposure
• Secluded WIMP Dark Matter
• Dark Matter Results From 54-Ton-Day Exposure of PandaX-II Experiment
• Precise Relic WIMP Abundance and its Impact on Searches for Dark Matter Annihilation
• Dark Matter Search Results from the Complete Exposure of the PICO-60 C${}_3$F${}_8$ Bubble Chamber
• A Tale of Tails: Dark Matter Interpretations of the Fermi GeV Excess in Light of Background Model Systematics
• Minimal Extension of the Standard Model Scalar Sector
• Constraining the Spin-Dependent WIMP-Nucleon Cross Sections with XENON1T
• Limits on spin-dependent WIMP-nucleon cross section obtained from the complete LUX exposure
• Multi-Component Dark Matter
• Particle Physics Models for the 17 MeV Anomaly in Beryllium Nuclear Decays
• Millisecond pulsars and the Galactic Center gamma-ray excess: the importance of luminosity function and secondary emission
• Improved limits on a hypothetical X(16.7) boson and a dark photon decaying into $e^{+}{e}^{-}$ pairs
• Improved limits for Higgs-portal dark matter from LHC searches
• Strong constraints on thermal relic dark matter from Fermi-LAT observations of the Galactic Center
• Foreground Mismodeling and the Point Source Explanation of the Fermi Galactic Center Excess
• The light U boson as the mediator of a new force, coupled to a combination of Q, B, L and dark matter
• Spurious Point Source Signals in the Galactic Center Excess
• Galactic Center Excess in Gamma Rays from Annihilation of Self-Interacting Dark Matter
• The Enigmatic Galactic Center Excess: Spurious Point Sources and Signal Mismodeling
• Dynamical Evidence For a Fifth Force Explanation of the ATOMKI Nuclear Anomalies
• Protophobic Light Vector Boson as a Mediator to the Dark Sector
• The new interaction suggested by the anomalous ${}^8$Be transition sets a rigorous constraint on the mass range of dark matter
• Is There a Sign of New Physics in Beryllium Transitions?

Cited by in corpus (1)

• Interpretation of XENON1T excess with MeV boosted dark matter