  UHE neutrinos may transfer highest cosmic-rays energies overcoming
$2.75K^\circ$ BBR and radio-waves opacities (the GZK cut off) from most distant
AGN sources at the age of the Universe. These UHE $\nu$ might scatter onto
those (light and cosmological) relic neutrinos clustered around our galactic
halo or nearby neutrino hot dark halo clustered around the AGN blazar and its
jets. The branched chain reactions from a primordial nucleon (via photo
production of pions and decay to UHE neutrinos) toward the consequent beam dump
scattering on galactic relic neutrinos is at least three order of magnitude
more efficient than any known neutrino interactions with Earth atmosphere or
direct nucleon propagation. Therefore the rarest cosmic rays (as the 320 EeV
event) might be originated at far $(\tilde{>} 100 Mpc)$ distances (as Seyfert
galaxy MCG 8-11-11); its corresponding UHE radiation power is in agreement with
the observed one in MeV gamma energies. The final chain products observed on
Earth by the Fly's Eye and AGASA detectors might be mainly neutron and
anti-neutrons and delayed, protons and anti-protons at symmetric off-axis
angles. These hadronic products are most probably secondaries of $W^+ W^-$ or
$ZZ$ pair productions and might be consistent with the last AGASA discoveries
of doublets and one triplet event.
