Dirac spinors and tachyon quantization

Dirac spinors for spin-1/2 free tachyons are derived from the Dirac and KleinGordon equations in terms of the standard helicity representation of the Poincare group and superluminal transformations (SLTs). It is shown that the proposed theory of second quantization is Lorentz invariant without inverting the spin-statistics relationship and without introducing indefinite pseudotachyonic states. Second quantized theory of spin-1/2 tachyons in the time-energy representation shows that tachyons are localized in time and that the most natural space for the description of tachyons is T^4-space. It has been emphasized that on passing from R^4-space (bradyons) to T^4-space (tachyons) via either, i.e., complex or real SLTs, tachyons behave in T^4-space exactly as bradyons do in R^4-space. T^4-space can be visualized as an internal space for a subluminal observer while R^ -space appears as an internal space for a superluminal observer.