Supersymmetric renormalization of the CKM matrix and new constraints on the squark mass matrices

We compute the finite renormalization of the Cabibbo-Kobayashi-Maskawa matrix induced by gluino-squark diagrams in the minimal supersymmetric standard model with nonminimal sources of flavor violation. Subsequently we derive bounds on the flavor-off-diagonal elements of the squark mass matrices by requiring that the radiative corrections to the Cabibbo-Kobayashi-Maskawa elements do not exceed the experimental values. Our constraints on the associated dimensionless quantities delta(dLR)(ij), j > i, are stronger than the bounds from flavor-changing neutral current (FCNC) processes if the gluino and squarks are heavier than 500 GeV. Our bound on vertical bar delta(uLR)(12)vertical bar is stronger than the FCNC bound from D - (D) over bar mixing for superpartner masses above 900 GeV. We further find a useful bound on vertical bar delta(uLR)(13)vertical bar, for which no FCNC constraint is known. Our results imply that it is still possible to generate all observed flavor violation from the soft supersymmetry-breaking terms without conflicting with present-day data on FCNC processes. We suggest that a flavor symmetry renders the Yukawa sector flavor-diagonal and the trilinear supersymmetry-breaking terms are the spurion fields breaking this flavor symmetry. We further derive the dominant supersymmetric radiative corrections to the couplings of charged-Higgs bosons and charginos to quarks and squarks.