  We propose a minimal set of weak-basis invariants in an extension of the SM
where one up-type isosinglet vector-like quark is introduced, which allows us
to obtain all the physical content of the CKM matrix. We present CP-odd
invariants of lower order in mass than the one in the SM, which may have
important consequences for Baryogenesis. We study the extreme chiral limit,
where the two lightest generations have vanishing mass, showing that in this
extension, contrary to the SM, CP violation can be observed in collisions much
above the electroweak scale.
