Revisiting the limits on dark matter annihilation cross-section and decay lifetime in light of electron and positron fluxes

Abstract

We revisit the upper bound on the annihilation cross-section, $⟨\ddot{I}ƒv⟩$ of a stable dark matter (DM) of mass $500-10^{14}$ GeV by considering five different channels: $W^{+}{W}^{-}$, $b\bar{b}$, $\hat{I}{¼}^{+}\hat{I}{¼}^{-}$, $\ddot{I}{„}^{+}\ddot{I}{„}^{-}$, and $e^{+}{e}^{-}$. We use the observed electron and positron fluxes from CALET, DAMPE, HESS, positron flux from AMS-02, and gamma-ray flux from HAWC, GRAPES-3, CASA-MIA to constrain the annihilation cross-section. We also consider unstable DM of mass $10^3-10^{16}$~GeV decaying to $W^{+}{W}^{-}$, $b\bar{b}$, $\hat{I}{¼}^{+}\hat{I}{¼}^{-}$, $\ddot{I}{„}^{+}\ddot{I}{„}^{-}$, and $e^{+}{e}^{-}$ and derive the corresponding lower bound on the DM lifetime, $\ddot{I}{„}_{\mathrm{DM}}$. We find that the latest AMS-02 data provide the most stringent constraints on $⟨\ddot{I}ƒv⟩$ for DM masses below 2 TeV, while HESS yields the strongest limits for $M_{\mathrm{DM}}\gtrsim 2$ TeV. The HESS gives a much more stringent limit on the DM lifetime, excluding $\ddot{I}{„}_{\mathrm{DM}\to \hat{\mathrm{I}}{¼}^{+}\hat{\mathrm{I}}{¼}^{-}}\lesssim \mathcal{O}(10^{30})$ s for a 10 TeV mass of DM. The limits on $⟨\ddot{I}ƒv⟩$ derived from the $e^{+}{e}^{-}$ flux are competitive with those from ${\hat{I}}^3$-ray and neutrino observations for DM masses in the range $10^5$--$10^{11}$ GeV, and become the most stringent beyond this range. For decaying DM, the $e^{+}{e}^{-}$ flux provides the strongest constraints on the DM lifetime over the mass range $10^3$--$10^9$ GeV.

v2: 1+18 pages, 12 captioned figures, 4 tables, version accepted for publication in JCAP