Energy and angular distribution of upward ultrahigh-energy neutrinos and signals of low scale gravity: Role of tau decay

We present extensive results and analysis of energy and angular distributions of diffuse UHE nu(e), nu(mu), and nu(tau) fluxes propagated through Earth, with and without augmentation of the standard model interactions by low scale gravity. With propagated fluxes in hand we estimate event rates in a 1 km(3) detector in ice with characteristics of ICECUBE. We determine that, at an 0.5 PeV energy threshold, there is a significant difference in the ratios of down shower events to upward muon events between the standard model and the low scale gravity cases with 1 TeV and 2 TeV mass scales. The same is true for the energy threshold at 5 PeV. Though the difference is large in all flux models, the statistical significance of this difference depends on the flux models, especially at 5 PeV and above. Both flavor assumptions, nu(e), nu(mu), nu(tau)::1, 2, 0 and nu(e), nu(mu), nu(tau)::1, 1, 1, and all flux models show large differences. Though rates of tagged events are low, we find that nu(tau) regeneration by tau decay may play an important role in disclosing deviations from standard model predictions at energies in the neighborhood of 1 PeV for 1-TeV-scale gravity, for example. We emphasize those analyses whose sensitivity to new physics is independent of the flux model assumed.