Hunting the Glashow Resonance with PeV Neutrino Telescopes

Abstract

The Glashow resonant scattering, $i.e$. ${\overline{\nu}^{}_{e} + e^{-} \rightarrow W^{-} \rightarrow \text{anything}}$, offers us a possibility of disentangling $\overline{\nu}^{}_{e}$ from the total astrophysical neutrino fluxes. Meanwhile, a great number of high-energy neutrino telescopes, with various detection mechanisms, are advancing towards a better understanding of one of the most energetic frontiers of the Universe. In this work, we investigate a connection between through-going muons at IceCube and the Glashow resonance signal through the channel $W^{-} \rightarrow \mu$. We find that for IceCube, muons from $\overline{\nu}^{}_{e}$ can induce a $\sim20\%$ excess of PeV events around the horizontal direction. However, the current statistic of IceCube is not enough to observe such an excess. We also address the novel possibility of $\overline{\nu}^{}_{e}$ detection via $W^{-} \rightarrow \tau$ at telescopes aiming to detect Earth-skimming and mountain-penetrating neutrinos. The subsequent hadronic decay of a tau will induce an extensive air shower which can be detected by telescopes with Cherenkov or fluorescence techniques. Similar to IceCube, it is challenging to observe the Glashow resonance excess from the Earth-skimming neutrinos. Nevertheless, we find it is promising to observe Glashow resonance events with a mountain as the target.