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

Abstract

The two messenger results of the GeV gamma-ray excess at the Galactic center and a probable antiproton excess in the recent AMS-02 observation suggest that these two anomalies may be owing to the same origin --- the dark matter (DM) annihilation into $b\bar{b}$, while these results seem in tension with the dwarf spheroidal galaxy observations. To give a compatible explanation about it, we consider the pseudoscalar DM particles $S_d^{+}{S}_d^{-}$ annihilating via $S_d^{+}{S}_d^{-}\to S_d^0{S}_d^0$, with the process mediated by a new scalar $\varphi$ and $S_d^0$ quickly decaying into $b\bar{b}$. For the particles $S_d^{+}$, $S_d^{-}$ and $S_d^0$ in a triplet with degenerate masses, the annihilation cross section of DM today is linearly dependent on the relative velocity $v_r$, and thus constraints from the dwarf spheroidal galaxies are relaxed. The parameter spaces are derived with corresponding constraints. Though traces from the new sector seem challenging to be disclosed at collider and in DM direct detections, the indirect search of the gamma-ray line from the $S_d^0$'s decay has the potential to shed light on DM annihilations, with the energy of the gamma-ray line $\sim m_{S_d^0}/2$, i.e. about 50$-$75 GeV.

19 pages, 9 figures, the accepted version

References in corpus (23)

• Results from a search for dark matter in the complete LUX exposure
• Combined Measurement of the Higgs Boson Mass in $pp$ Collisions at $\sqrt{s}=7$ and 8 TeV with the ATLAS and CMS Experiments
• Secluded WIMP Dark Matter
• Dark Matter Results from First 98.7-day Data of PandaX-II Experiment
• Searching for Dark Matter Annihilation in Recently Discovered Milky Way Satellites with Fermi-LAT
• Background model systematics for the Fermi GeV excess
• Measurement of Higgs boson production in the diphoton decay channel in $pp$ collisions at center-of-mass energies of 7 and 8 TeV with the ATLAS detector
• A Tale of Tails: Dark Matter Interpretations of the Fermi GeV Excess in Light of Background Model Systematics
• Velocity Dispersion Profiles of Seven Dwarf Spheroidal Galaxies
• A taste of dark matter: Flavour constraints on pseudoscalar mediators
• Ultra Minimal Technicolor and its Dark Matter TIMP
• GeV excess in the Milky Way: The Role of Diffuse Galactic gamma ray Emission template
• The velocity dispersion and mass profile of the Milky Way
• WIMPs at the Galactic Center
• The Effective Hooperon
• Co-Decaying Dark Matter
• Dark Matter Interpretation of the Fermi-LAT Observation Toward the Galactic Center
• Galactic Center Excess in Gamma Rays from Annihilation of Self-Interacting Dark Matter
• The Gamma-Ray Pulsar Population of Globular Clusters: Implications for the GeV Excess
• Low Mass X-Ray Binaries in the Inner Galaxy: Implications for Millisecond Pulsars and the GeV Excess
• Hidden sector explanation of $B$-decay and cosmic ray anomalies
• Young Pulsars and the Galactic Center GeV Gamma-ray Excess
• Study of WIMP annihilations into a pair of on-shell scalar mediators

Cited by in corpus (7)

• The Dawn of FIMP Dark Matter: A Review of Models and Constraints
• GeV-Scale Thermal WIMPs: Not Even Slightly Dead
• Scrutinizing the evidence for dark matter in cosmic-ray antiprotons
• Cosmic-ray Antinuclei as Messengers of New Physics: Status and Outlook for the New Decade
• Dark Matter Annihilation into Four-Body Final States and Implications for the AMS Antiproton Excess
• Explanation of the 511 keV line: Cascade annihilating dark matter with the ${}^8$Be anomaly
• Velocity-dependent self-interacting dark matter from thermal freeze-out and tests in direct detections