  The discovery of high-energy astrophysical neutrinos by IceCube has opened a
new window to the Universe. However, the origin of these neutrinos is still a
mystery, and some of them could be a result of dark matter interactions such as
decay. Next generation gigaton water-Cherenkov neutrino telescope, KM3NeT, is
expected to offer significantly improved energy resolution in the cascade
channel, and advantageous viewing condition to the Galactic Center; both
important for searches of dark matter decay signals. We study the sensitivity
of KM3NeT on dark matter decays by performing a mock likelihood analysis for
both cascade and track type events, taking into account both angular and energy
information. We find that, combining both channels, KM3NeT is expected to
produce world leading limits on dark matter decay lifetime in the PeV mass
range, and could test some of the dark matter hints in the current IceCube
data.
