Oscillating Flavors in Massless Neutrinos
  By considering Dirac's equation using quaternions ($\mathbb{H}$) with their greater degree of freedom in imaginaries, it is shown that a model can be created with oscillations among flavors even if the particles, are massless. Furthermore the solutions are spin $\frac{1}{2}$ and have helicities depending on whether their energy is positive or negative. 
Lester C. Welch
physics.gen-ph