Antineutrino-neutrino and antineutrino-electron resonant annihilation through rho and other vector mesons

The \bar{nu}e^- --> pi^- pi^0 and nu e^+ --> pi^+ pi^0 reaction have a resonant structure whenever the energy of the s–channel equals the mass of a J^P=1^- vector meson. The resonant cross sections are of the order 10^{-38} cm^2 and correspond to cosmic ray antineutrino energies in the range 0.2 to 2 TeV. A similar structure occurs in the annihilation of cosmic ray antineutrinos with a relic (background) neutrino. For m_{nu} <= 10^{-3} eV the resonant energy is above GZK limit and their decay products include multiple gamma–rays. Possible detection schemes are discussed, especially those which rely on Cherenkov radiation.