Heavy decaying dark matter and IceCube high energy neutrinos

Understand

We examine the hypothesis of decaying heavy dark matter (HDM) in the context of the IceCube highest energy neutrino events and recent limits on the diffuse flux of high-energy photons.

• We consider dark matter (DM) particles $X$ of mass $10^{6}\leq M_X\leq~10^{16}$ GeV decaying on tree level into $X \rightarrow \nu \bar{\nu}$, $X \rightarrow e^+e^-$ and $X \rightarrow q \bar{q}$.
• The full simulation of hadronic and electroweak decay cascades and the subsequent propagation of the decay products through the interstellar medium allows us to determine the permitted values of $M_X$.
• We show that for leptonic decay channels it is possible to explain the IceCube highest energy neutrino signal without overproducing high-energy photons for $M_X~\lesssim~5.5 \cdot 10^{7}$ GeV and $1.5 \cdot 10^{8}~\lesssim~M_X~\lesssim~1.5 \cdot 10^{9}$ GeV, while hadronic decays contradict the gamma-ray limits for almost the whole range of $M_X$ values considered.