A new Dirac-type equation for tachyonic neutrinos

Based on experimental evidences supporting the hypothesis that neutrinos might be tachyonic fermions, a new Dirac-type equation is proposed and a spin-1/2 tachyonic quantum theory is developed. The new Dirac-type equation provides a solution for the puzzle of negative mass-square of neutrinos. This equation can be written in two spinor equations coupled together via nonzero mass while respecting the maximum parity violation, and it reduces to one Weyl equation in the massless limit. Some peculiar features of tachyonic neutrino are discussed in this theoretical framework.