  CP violation plays a privileged role in our quest for new physics beyond the
electroweak standard model (SM). In the SM the violation of CP in the weak
interactions has a single source: the phase of the quark mixing matrix (the CKM
matrix, for Cabibbo-Kobayashi-Maskawa). Most extensions of the SM exhibit new
sources of CP violation. For instance, the truly minimal supersymmetric
extension of the SM (CMSSM) has two new phases in addition to the CKM phase.
Given that CP violation is so tiny in the kaon system, is still largely
unexplored in B physics and is negligibly small in the electric dipole moments,
it is clear that new physics may have a good chance to manifest some departure
from the SM in this particularly challenging class of rare phenomena. On the
other hand, it is also apparent that CP violation generally represents a major
constraint on any attempt at model building beyond the SM. In this review we
tackle these two sides of the relation between CP violation and new physics.
Our focus will be on the potentialities to use CP violation as a probe on
Supersymmetric (SUSY) extensions of the SM. We wish to clarify the extent to
which such indirect signals for SUSY are linked to a fundamental theoretical
issue: is there a relation between the mechanism that originates the whole
flavor structure and the mechanism that is responsible for the breaking of
supersymmetry? Different ways to answer this question lead to quite different
expectations for CP violation in B physics.
