Rates of Horizontal Tau Air-Showers observable by satellites

Abstract

Up-going and Horizontal Tau Air-Showers, UpTaus and HorTaus, may trace Ultra High Energy Neutrino Tau Earth Skimming at the edge of the horizon. We show that such events even for minimal GZK neutrino fluxes could be detected by space telescopes such as the EUSO project. These Horizontal Tau Showers will track very long fan-like, multi-finger showers whose signature would be revealed by EUSO, OWL experiments. Moreover the additional imprint of their young secondaries muon, electron pairs and gamma bundles flashes might allow to disentangle their nature from the older UHECR secondaries in horizontal showers. Indeed at large zenith angles, the muon, electron pairs and gamma number for far and old Ultra High Energy Cosmic Rays, becomes comparable. On the contrary up-ward muon bundles from UpTaus and HorTaus (as well as by anti-neutrino electron + electron resonance at Glashow peak) may arise within a young shower with a gamma-muon ratio as large as 10^2. Such a very characteristic imprint maybe observed by Crown detector arrays on Mountain, planes or balloons in space, as well as by gamma satellites in Space. We estimate the UpTaus and HorTaus rate from the Earth and the consequent event rate of +/-mu bundles, whose flux at 92^o -97^o may exceed the up-going muon flux induced by the atmospheric neutrino, by one or two order of magnitude.