Lightest Nuclei in UHECR versus Tau Neutrino Astronomy
  UHECR may be either nucleons or nuclei; in the latter case the Lightest
Nuclei, as He, Li, Be, explains at best the absence of Virgo signals and the
crowding of events around Cen-A bent by galactic magnetic fields. This model
fit the observed nuclear mass composition discovered in AUGER. However UHECR
nucleons above GZK produce EeV neutrinos while Heavy Nuclei, as Fe UHECR do not
produce much. UHECR He nuclei at few tens EeV suffer nuclear fragmentation
(producing low energetic neutrino at tens PeVs) but it suffer anyway photo-pion
GZK suppression (leading to EeV neutrinos) once above one-few 10^{20} eV. Both
these cosmogenic UHE secondary neutrinos signals may influence usual predicted
GZK Tau Neutrino Astronomy in significant and detectable way; the role of
resonant antineutrino electron-electron leading to Tau air-shower may also
rise.
