Galactic PeV neutrinos from dark matter annihilation

Understand

The IceCube Neutrino Observatory has observed highly energetic neutrinos in excess of the expected atmospheric neutrino background.

• It is intriguing to consider the possibility that such events are probing physics beyond the standard model.
• In this context, $\mathcal{O}$(PeV) dark matter particles decaying to neutrinos have been considered while dark matter annihilation has been dismissed invoking the unitarity bound as a limiting factor.
• However, the latter claim was done ignoring the contribution from dark matter substructure, which for PeV Cold Dark Matter would extend down to a free streaming mass of $\mathcal{O}$($10^{-18}$M$_\odot$).