Effective Higgs vertices in the generic MSSM

In this article we consider chirally enhanced corrections to Higgs vertices in the most general MSSM. We include the contributions stemming from bilinear terms, from the trilinear A terms, and from their nonholomorphic analogues, the A' terms, which couple squarks to the wrong'' Higgs field. We perform a consistent renormalization of the Higgs vertices beyond the decoupling limit (M-SUSY -> infinity), using a purely diagrammatic approach. The cancellation of the different contributions in and beyond the decoupling limit is discussed and the possible size of decoupling effects which occur if the supersymmetry particles are not much heavier than the electroweak scale are examined. In the decoupling limit we recover the results obtained in the effective-field-theory approach. For the nonholomorphic A' terms we find the well known tan beta enhancement in the down sector similar to the one for terms proportional to mu. Because of the a priori generic flavor structure of these trilinear terms large flavor-changing neutral Higgs couplings can be induced. We also discover new tan beta enhanced contributions involving the usual holomorphic A terms, which were not discussed before in the literature. These corrections occur only if also flavor-diagonal nonholomorphic corrections to the Higgs couplings are present. This reflects the fact that the A terms, and also the chirality-changing self-energies, are physical quantities and cannot be absorbed into renormalization constants.