On the non-detection of Glashow resonance in IceCube

Abstract

Electron anti-neutrinos at the Glashow resonance (GR, at E<inf>ν¯<inf>e</inf></inf>∼6.3 PeV) have an enhanced probability to be detected. With three neutrinos detected by IceCube in the (1–2) PeV energy range at present, one would expect that about 1 to 4 GR ν¯<inf>e</inf> should have been detected. The high-energy ∼8.7 PeV muon neutrino detected by IceCube may not be a GR event. If so, we expect to detect 50 to 70 GR ν¯<inf>e</inf>, then one would have a “missing Glashow-resonance problem”. This would suggest (1) that pγ interaction rather than pp interaction is the dominant channel to produce the observed IceCube high-energy neutrinos; (2) that multi-pion pγ interactions are suppressed; and (3) that the magnetic field and photon energy density in the pγ emission region is such that significant μ⁺ cooling occurs before decaying, yet π⁺'s essentially do not cool before decaying.