Soft Yukawa couplings in supersymmetric theories

The possibility of radiatively generated fermion masses arising from chiral flavor violation in soft supersymmetry-breaking terms is explored. Vacuum stability constraints are considered in various classes of models, and allo w in principle all of the first- and second-generation quarks and leptons a nd the b-quark to obtain masses radiatively. Radiatively induced Higgs-ferm ion couplings have non-trivial momentum-dependent form factors, which at lo w momentum are enhanced with respect to the case of tree-level Yukawa coupl ings. These form factors may be probed by various sum rules and relations a mong Higgs boson decay widths and branching ratios to fermion final states. An apparent, large, hard violation of supersymmetry also results for Higgs ino couplings. Mixing between left- and right-handed scalar superpartners i s enhanced. A radiative muon mass is shown to lead to a relatively large an d potentially measurable contribution to the muon anomalous magnetic moment . If the light-quark masses arise radiatively, the neutron electric dipole moment is suppressed by a natural phase alignment between the masses and di pole moment, and is below the current experimental bound. The possibility o f neutrino masses arising from softly broken lepton number, and concomitant enhanced sneutnino-antisneutrino oscillations, is briefly discussed. (C) 1 999 Elsevier Science B.V. All rights reserved.