  Quantum field theory of space-like particles is investigated in the framework
of absolute causality scheme preserving Lorentz symmetry. It is related to an
appropriate choice of the synchronization procedure (definition of time). In
this formulation existence of field excitations (tachyons) distinguishes an
inertial frame (privileged frame of reference) via spontaneous breaking of the
so called synchronization group. In this scheme relativity principle is broken
but Lorentz symmetry is exactly preserved in agreement with local properties of
the observed world. It is shown that tachyons are associated with unitary
orbits of Poincar\'e mappings induced from $SO(2)$ little group instead of
$SO(2,1)$ one. Therefore the corresponding elementary states are labelled by
helicity. The cases of the helicity $\lambda = 0$ and $\lambda =
\pm\frac{1}{2}$ are investigated in detail and a corresponding consistent field
theory is proposed. In particular, it is shown that the Dirac-like equation
proposed by Chodos et al., inconsistent in the standard formulation of QFT, can
be consistently quantized in the presented framework. This allows us to treat
more seriously possibility that neutrinos might be fermionic tachyons as it is
suggested by experimental data about neutrino masses.
