First signs of the Glashow resonance from an astrophysical (anti)neutrino

The Glashow resonance describes the resonant formation of an on-mass W- boson via the scattering of an electron antineutrino and an electron, a process first predicted in 1959. In the electron rest frame, the requisite neutrino energy of 6.3 PeV lies beyond the reach of terrestrial accelerators. However, the discovery of a diffuse flux of astrophysical neutrinos by IceCube gave rise to the possibility of detecting the resonance via high-energy (anti)neutrinos from outer space. Such interactions provide additional information on the charge and flavor of the astrophysical neutrino, and can constrain production mechanisms at the highest energy scales of our Universe. In this talk, I will discuss IceCube’s first Glashow resonance candidate. The unique signatures in data ensures that it is of astrophysical origin and improve directional localization. With a reconstructed energy of 6.05 ± 0.72 PeV, and assuming the best-fit global diffuse flux, the probability that the event is produced by deep inelastic scattering is 0.01.