Neutrino Signals from Annihilating/Decaying Dark Matter in the Light of Recent Measurements of Cosmic Ray Electron/Positron Fluxes

Abstract

The excess of cosmic-ray electron and positron fluxes measured by the PAMELA satellite and ATIC balloon experiments may be interpreted as the signals of the dark matter annihilation or decay into leptons. In this letter we show that the dark matter annihilation/decay which reproduces the electron/positron excess may yield a significant amount of high-energy neutrinos from the Galactic center. In the case, future kilometer-square size experiments may confirm such a scenario, or even the Super-Kamiokande results already put constraints on some dark matter models.

Figures (4)

• Figure 1: The positron fraction (top) and total electron and positron flux from the annihilation (bottom) from dark matter annihilation. We take the mass and annihilation cross section as $m=0.7~$TeV and $\langle \sigma v\rangle =5\times 10^{-24}~{\rm cm^3s^{-1}}$ for the mode into $e^+ e^-$ (solid), $m=1~$TeV and $\langle \sigma v\rangle =1.5\times 10^{-23}~{\rm cm^3s^{-1}}$ for the mode into $\mu^+ \mu^-$ (dashed), $m=1.2~$TeV and $\langle \sigma v\rangle =2\times 10^{-23}~{\rm cm^3s^{-1}}$ for the mode into $\tau^+ \tau^-$ (dotted). Results of PAMELA, ATIC2, BETS and PPB-BETS are plotted.
• Figure 2: Expected up-going muon flux from the dark matter annihilation (top) and decay (bottom) as a function of the cone half angle from the Galactic center. SK limits are also shown. Here, we assume the the dark matter annihilates/decays into left-handed leptons ($\tau_L^- \tau_R^+$ and $\nu_\tau \bar{\nu}_\tau$) shown by "Left" or right-handed leptons ($\tau_R^- \tau_L^+$) shown by "Right". Annihilating Dark matter models correspond to those used in Fig. \ref{['fig:eflux']}. For the case of decaying dark matter, we used $\Gamma = 1.5\times 10^{-26}~{\rm s}^{-1}$ and $m=2.4~$TeV. The dark matter density profile is assumed to be the NFW and isothermal profiles.
• Figure 3: Same as Fig. \ref{['fig:tau']}, but for annihilating (decaying) into $\mu^- \mu^+$. For the case of decaying dark matter, we used $\Gamma = 1\times 10^{-26}~{\rm s}^{-1}$ and $m=2~$TeV.
• Figure 4: Same as Fig. \ref{['fig:tau']}, but for annihilating (decaying) into $e^-e^+$. For the case of decaying dark matter, we used $\Gamma = 4\times 10^{-26}~{\rm s}^{-1}$ and $m=1.4~$TeV.