We construct the most general effective Lagrangian of the matter sector of
the standard model, including mixing and CP violating terms. The Lagrangian
contains the effective operators that give the leading contribution in the
ories where the physics beyond the standard model shows at a scale Lambda m
uch greater thanM(W). We perform the diagonalization and passage to the phy
sical basis in full generality. We determine the contribution to the differ
ent observables and discuss the possible new sources of CP violation, the i
dea being to be able to gain some knowledge about new physics beyond the st
andard model from general considerations, without having to compute model b
y model. The values of the coefficients of the effective Lagrangian in some
theories, including the standard model, are presented and we try to draw s
ome general conclusions about the general pattern exhibited by physics beyo
nd the standard model in what concerns CP violation. in the process we have
had to deal with two theoretical problems which are very interesting in th
eir own: the renormalization of the CKM matrix elements and the wave functi
on renormalization in the on-shell scheme when mixing is present.