Glashow resonance as a window into cosmic neutrino sources

Abstract

The Glashow resonance at ${E}_{\ensuremath{\nu}}=6.3\text{ }\text{ }\mathrm{PeV}$ is a measure of the ${\overline{\ensuremath{\nu}}}_{e}$ content of the astrophysical neutrino flux. The fractional ${\overline{\ensuremath{\nu}}}_{e}$ content depends on the neutrino production model at the cosmic neutrino source, and the environment at the source. Thus, the strength of the Glashow resonance event rate is a potential window into astrophysical sources. We quantify the ``Glashow resonometer'' and comment on the significance that no Glashow events are observed in the IceCube three-year data.