Ultrahigh-Energy Neutrinos from Primordial Black Holes

The KM3NeT Collaboration recently announced the detection of a neutrino with energy 220 PeV. One possible source of such ultrahigh-energy particles is the rapid emission of energetic Hawking radiation from a primordial black hole (PBH) near the end of its evaporation lifetime. The mass distribution for PBHs features a power-law tail for small masses; a small subset of PBHs would be undergoing late-stage evaporation today. We find that recent high-energy neutrino events detected by the IceCube and KM3NeT Collaborations, with energies <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mi mathvariant="script">O</a:mi><a:mo stretchy="false">(</a:mo><a:mn>1</a:mn><a:mo>−</a:mo><a:msup><a:mrow><a:mn>10</a:mn></a:mrow><a:mrow><a:mn>2</a:mn></a:mrow></a:msup><a:mo stretchy="false">)</a:mo><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi>PeV</a:mi></a:mrow></a:math>, are consistent with event-rate expectations if a significant fraction of the dark matter consists of PBHs.