Heavy decaying dark matter and large-scale anisotropy of high-energy cosmic rays

We examine the role of the large--scale anisotropy of the high--energy cosmic ray distribution in a search for the heavy decaying dark matter (DM) signal. Using recent anisotropy measurements from the extensive air shower (EAS) observatories we constrain the lifetime of the DM particles with masses $10^{7}~\leq~M_X~\leq~10^{16}$ GeV. These constraints appear to be weaker than that obtained with the high energy gamma-ray limits. We also estimate the desired precision level for the anisotropy measurements to discern the decaying DM signal marginally allowed by the gamma-ray limits and discuss the prospects of the DM search with the modern EAS facilities.