Recent measurements made by the Alpha Magnetic Spectrometer (AMS) have detected accurate positron flux for an energy range of 1–1000 GeV. The energy spectrum can be best described by two source terms: the low-energy background diffusion term and an unknown high-energy source term. In this article, we discuss the possibility of the emission of positrons originating from dark matter annihilation in two nearby black hole X-ray binaries A0620-00 and XTE $\mathrm{J}1118+480$. We show that the dark matter density spikes around these two black holes can best produce the observed AMS-02 high-energy positron flux due to dark matter annihilation with rest mass $m_{\mathrm{DM}}\approx 8000\mathrm{GeV}$ via the $W^{+}{W}^{-}$ annihilation channel. This initiates a new proposal to account for the unknown high-energy source term in the AMS-02 positron spectrum.

Close

PrevNext

View figure in article

• Dark matter
• Particle dark matter