Enhanced signal of astrophysical tau neutrinos propagating through Earth

Earth absorbs $\text{nue}$ and $\text{numu}$ of energies above about 100 TeV. As is well-known, although $\text{nutau}$ will also disappear through charged-current interactions, the $\text{nutau}$ flux will be regenerated by prompt tau decays. We show that this process also produces relatively large fluxes of secondary $\text{nube}$ and $\text{nubmu}$, greatly enhancing the detectability of the initial $\text{nutau}$. This is particularly important because at these energies $\text{nutau}$ is a significant fraction of the expected astrophysical neutrino flux, and only a tiny portion of the atmospheric neutrino flux.