Dark matter “transporting” mechanism explaining positron excesses
We propose a novel mechanism to explain the positron excesses, which are observed by satellite-based telescopes including PAMELA and AMS-02, in dark matter (DM) scenarios. The novelty behind the proposal is that it makes direct use of DM around the Galactic Center where DM populates most densely, allowing us to avoid tensions from cosmological and astrophysical measurements. The key ingredients of this mechanism include DM annihilation into unstable states with a very long laboratory-frame life time and their “retarded” decay near the Earth to electron-positron pair(s) possibly with other (in)visible particles. We argue that this sort of explanation is not in conflict with relevant constraints from big bang nucleosynthesis and cosmic microwave background. Regarding the resultant positron spectrum, we provide a generalized source term in the associated diffusion equation, which can be readily applicable to any type of two-“stage” DM scenarios wherein production of Standard Model particles occurs at completely different places from those of DM annihilation. We then conduct a data analysis with the recent AMS-02 data to validate our proposal.
KeywordsBeyond Standard Model Cosmology of Theories beyond the SM
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- AMS collaboration, M. Aguilar et al., Unlocking the Secrets of the Cosmos: The First Five years of AMS on the International Space Station, (2016).Google Scholar
- AMS collaboration, M. Aguilar et al., First Result from the Alpha Magnetic Spectrometer on the International Space Station: Precision Measurement of the Positron Fraction in Primary Cosmic Rays of 0.5-350 GeV, Phys. Rev. Lett. 110 (2013) 141102 [INSPIRE].
- AMS collaboration, L. Accardo et al., High Statistics Measurement of the Positron Fraction in Primary Cosmic Rays of 0.5-500 GeV with the Alpha Magnetic Spectrometer on the International Space Station, Phys. Rev. Lett. 113 (2014) 121101 [INSPIRE].
- D. Kim, J.-C. Park and S. Shin, Cosmological aspect of models conceiving the dark matter “transporting” mechanism, in progress.Google Scholar