The Imaginary Mass of the Neutrino

This paper proposes that the elusive neutrino is a space-like unitary irreducible representation of the Poincare Group. Although its imaginary mass is not a physical observable, its square is. This amount is found experimentally to be negative. Therefore, the neutrino is a tachyon with a measurable property; the square of its mass. This paper does not resolve the problem of how the neutrino propagates in the space. Further studies are necessary to address this question.