  According to the experimental data, it is still controversial whether the
neutrinos, especially the electron-neutrino and muon-neutrino, can be
considered as the fermionic spinorial tachyons, and there is still no reliable
report on the existence of the right-handed neutrinos. In this letter, we show
that the neutrinos with the single handedness can not be the tachyons, but only
those of the both handedness can be. Several implications of this result are
discussed.
