Explaining the PeV Neutrino Fluxes at KM3NeT and IceCube with Quasiextremal Primordial Black Holes

The KM3NeT experiment has recently observed a neutrino with an energy around 100 PeV, and IceCube has detected five neutrinos with energies above 1 PeV. While there are no known astrophysical sources, exploding primordial black holes could have produced these high-energy neutrinos. For Schwarzschild black holes this interpretation results in tensions between the burst rates inferred from the KM3NeT and IceCube observations, with indirect constraints from the extragalactic gamma-ray background and with the nonobservation of an associated gamma-ray signal at LHAASO. In this Letter we show that if there is a population of primordial black holes charged under a new dark u(1) symmetry which spend most of their time in a quasiextremal state, the neutrino emission at 1 PeV may be more suppressed than at 100 PeV. The burst rates implied by the KM3NeT and IceCube observations and the indirect constraints can then all be consistent at 1σ, and no associated gamma-ray signal was expected at LHAASO. Furthermore, these black holes could constitute all of the observed dark matter in the universe.