High Energy Neutrino and Tau Airshowers in Standard and New Physics

High Energy Neutrino may lead to a New High Energy Astronomy. Neutrino interaction in matter at PeVs- EeVs may behave differently from Standard Model predictions because possible TeV Gravity scenario. While traditional km^3 neutrino underground detector will be uneasy to disentangle the Gravity TeV scenario any new Horizontal Tau Air-Shower detectors at PeVs tau energy, beyond Mountain Chains, will be greatly enhanced and it may probe fruit-fully the New TeV Physics imprint. Moreover observing upcoming and horizontal tau air-showers {UPTAUS, HORTAUS} from high mountains toward Mount Chains or along widest Earth Crust crown masses at the Horizons edges, Ultra High Energy,UHE, nu_{tau} and its consequent tau lepton decay in flight, will greatly amplify any single UHE nu_{tau} track and it will test, at highest energies, huge volumes comparable to underground km^3 ones; observing UPTAUS and HORTAUs from higher balloons or satellites at orbit altitudes, at GZK energies, the Horizontal Crown effective Masses may even exceed 150 km^3. These Highest energies (10^{19} eV) nu astronomy are tuned to test the needed abundant nu fluence in GZK Z-Showering model: in this scenario ZeV Ultra High Energy neutrino are hitting on relic light (0.1-5 eV masses) anti-neutrinos, clustered in dark hot halos, creating UHE Z bosons whose decay in flight may be the hadronic secondaries observed on Earth atmosphere as UHECR, isotropically spread along the cosmic edges and clustered toward few correlated BL Lac sources.