Cascade reconstruction at the Glashow resonance in Icecube

IceCube is a cubic kilometer neutrino detector located at the South Pole. Observation of the spectrum near the characteristic energy E_ν ' 6.3 PeV of the Glashow resonance, the interaction of anti-neutrinos with atomic electrons via ν¯_e + e⁻ → W⁻, is of particular interest, since it offers the unique possibility to determine the contribution from electron anti-neutrinos to the diffuse flux of astrophysical neutrinos. The flux of electron anti-neutrinos, if observed, provides new constraints on the possible production mechanisms for high-energy neutrinos in astrophysical sources. The dominant signatures of neutrino interactions at the Glashow resonance are particle showers (cascades), originating from hadronic W⁻ decay. The corresponding signal is anticipated to exceed the continuum of deep-inelastic-scattering induced cascades by up to a factor of 10. Assuming an extraterrestrial electron neutrino flux E²Φ = 1 × 10^{− 8} GeV · cm^{− 2} · s^{− 1} · sr^{− 1} and a neutrino to anti-neutrino ratio of (ν_e : ν¯_e) = (1: 1), which is a generic prediction for pure proton-proton (pp) sources, we expect to detect 0.9 events per year that are contained within the instrumented volume of IceCube.