One way to probe dark matter is to find whether it decays into neutrinos. Heavy dark matter, with a mass larger than 10^7 GeV, might decay into ultra-high-energy neutrinos, with energies larger than 10^7 GeV. In the next 10-20 years, a new generation of ultra-high-energy neutrino telescopes, like IceCube-Gen2, should be able to look for these neutrinos.

However, ultra-high-energy neutrinos not made in dark matter decay represent an unknown background to these dark-matter searches. These are the cosmogenic and astrophysical ultra-high-energy neutrinos, first predicted by Berezinsky in 1969, that we have been looking for for the the last 50+ years.

Essentially, while neutrinos from dark matter are concentrated in directions near the Galactic Center—where dark matter is more abundant—the flux of non-dark-matter neutrinos is isotropic. If that flux is high, it could obscure the signal of neutrinos from dark-matter decay.

In a recent paper led by Damiano Fiorillo, and co-authored by Víctor Valera and Walter Winter, we show that future searches for ultra-high-energy neutrinos should be able to survive the existence of even a medium-sized background of cosmogenic or astrophysical neutrinos, even if that background is not known a priori.

Discovery of heavy dark matter decay into ultra-high-energy neutrinos, or constraints on it, are relatively safe from backgrounds:

Read more at

Searches for dark matter decay with ultra-high-energy neutrinos endure backgrounds
Damiano F. G. Fiorillo, Victor Valera, Mauricio Bustamante, Walter Winter
2307.02538 astro-ph