Dark matter interpretation of the Fermi -LAT observation toward the Galactic Center

Abstract

The center of the Milky Way is predicted to be the brightest region of γ-rays generated by selfannihilating dark matter particles. Excess emission about the Galactic center above predictions made for standard astrophysical processes has been observed in γ-ray data collected by the Fermi Large Area Telescope. It is well described by the square of an NFW dark matter density distribution. Although other interpretations for the excess are plausible, the possibility that it arises from annihilating dark matter is valid. In this paper, we characterize the excess emission as annihilating dark matter in the framework of an effective field theory. We consider the possibility that the annihilation process is mediated by either pseudo-scalar or vector interactions and constrain the coupling strength of these interactions by fitting to the Fermi Large Area Telescope data for energies 1-100 GeV in the 15 • × 15 • region about the Galactic center using self-consistently derived interstellar emission models and point source lists for the region. The excess persists and its spectral characteristics favor a dark matter particle with a mass in the range approximately from 50 to 190 (10 to 90) GeV and annihilation cross section approximately from 1×10 −26 to 4×10 −25 (6×10 −27 to 2×10 −25 ) cm 3 /s for pseudo-scalar (vector) interactions. We map these intervals into the corresponding WIMP-neutron scattering cross sections and find that the allowed range lies well below current and projected direct detection constraints for pseudo-scalar interactions, but are typically ruled out for vector interactions.

Interpretation of the gamma-ray excess and AMS-02 antiprotons: Velocity dependent dark matter annihilations

“…One possible DM signature is the Galactic center (GC) 1−3 GeV gamma-ray excess, which may be due to the weakly interacting massive particle (WIMP) type DM annihilating into bb, cc, qq (light quarks u, d, s), ττ et al [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15], e.g. WIMPs in a mass range about 35−74 GeV annihilating into bb with the cross section about (1−3)×10 −26 cm 3 /s.…”

Simplified dark matter models in the light of AMS-02 antiproton data

“…As the dark matter-nucleon elastic scattering cross sections induced by the simplified models we consider are spin-dependent, the most stringent constraints come from collider search and indirect detection of dark matter [41][42][43][44]. LHC performed dark matter search using events with large missing transverse momentum plus energetic jets [41] and dijet events [42,43] at 13 TeV collisions.…”

Two component WIMP–FImP dark matter model with singlet fermion, scalar and pseudo scalar

“…Both dark matter candidates in the present "WIMP-FImP" framework are insensitive to direct detection experimental bounds and the spin independent direct detection cross-section is far below the upper limit given by the LUX, PandaX-II DM direct search results. While this work is being completed, we came to know about a new work [158] on the analysis of the Fermi-LAT GC gamma ray excess for pseudo scalar interaction of dark matter using a different ROI (15 0 × 15 0 ) about GC with interstellar emission models (IEMs) and point sources. A detailed study of the results presented in [158] is beyond the scope of this work and we wish to test these results for pseudo scalar interactions in our model in a future work.…”