Discovering Ultra High Energy Neutrinos by Horizontal and Upward tau   Air-Showers: Evidences in Terrestrial Gamma Flashes?
  Ultra high energy neutrinos UHE neutrino Tau, anti-neutrino Tau, anti-neutrino electron at PeVs, and higher energy may induce tau air-showers whose detectability is million to billion times amplified by their secondaries. We considered UHE nu_{tau}- N and UHE bar\nu_{e}- e interactions beyond mountains as a source of such horizontal amplified Tau air-showers. We also consider vertical upward UHE nu_{tau}-N interaction on Earth crust leading to UHE Tau airshowers {UPTAUS} or at the horizont edges {HORTAUS} and their beaming toward high mountains gamma, X, Cherenkov detectors on mountains. We show their detectability. We notice that such rare upward Tau air-shower, UPTAUS and HORTAUS, may hit even nearby airlines, ballons, satellite and flash them by short diluted gamma-burst at the edge of Gamma Ray Observatory (GRO) detection threshold. We suggest the identification of these events with recent discovered (BATSE) Terrestrial Gamma Flashes and we claim their probable UHE Tau by UHE nu_\tau origin. From these data approximated UHE nu_tau flux and Delta m_{nu_mu \nu_tau} lower bound are derived. Known X-gamma-{TeV} active galactic and extragalactic sources have been identified in most TGF arrival directions. Maximal EGRET activity in galactic Center overlap with maximal TGF flux. The UHECR AGASA an-isotropy at 10^{18} eV shows also possible correlations with TGF events. The unique UHECR triplet in AGASA clustering, pointing toward BL Lac 1ES0806+524, finds, within its error box, a corresponding TGF event, BATSE (Trigger 2444). Finally a partial TGF Galactic signature, combined with above correlations suggests an astrophysical tau origin of TGF events. 
Daniele Fargion (Physics Department Rome Univ.1, INFN, Rome, Italy)