UHE and EHE neutrino induced taus inside the Earth

Tau neutrinos interacting inside the Earth produce τ leptons which thereafter can decay inside the atmosphere. The propagation of extremely energetic ντ ’s and τ ’s through the Earth is studied by means of a detailed Monte Carlo simulation, taking into account all major mechanisms of ντ interactions and τ energy loss as well as decay modes. The rates of τ ’s emerging from the Earth are determined as a function of τ ’s energy for several cosmic neutrino models.