  Non-tachyonic superluminal sectors of matter (superbradyons), with critical
speeds in vacuum much larger than the speed of light, can quite naturally exist
and play an important role in both cosmic-ray physics (anomalous high-energy
events) and cosmology (big-bang physics, alternatives to inflation, dark
matter...). They can even be the real "elementary" particles. An updated
discussion of the subject is presented, in relation with recent theoretical and
experimental results. Prospects for future searches are also reexamined.
Lorentz symmetry violation (LSV) models based on mixing with superbradyons are
compared with LDRK (linearly deformed relativistic kinematics) and QDRK
(quadratically deformed relativistic kinematics) such as defined in our
previous paper physics/0003080 .
