  A quantum field model for Dirac-like tachyons respecting a frame-dependent
interpretation rule, and thus inherently breaking Lorentz invariance, is
defined. It is shown how the usual paradoxa ascribed to tachyons, instability
and acausality, are resolved in this model, and it is argued elsewhere that
Lorentz symmetry breaking is necessary to permit perturbative renormalizability
and causality. Elimination of negative-normed states results in only
left-handed particles and right-handed antiparticles, suitable for describing
the neutrino. In this context the neutron beta decay spectrum is calculated
near the end point for large, but not ultrarelativistic preferred frame speed,
assuming a vector weak interaction vertex.
