Scherk-Schwarz Supersymmetry Breaking for Quasi-localized Matter Fields and Supersymmetry Flavor Violation

We examine the soft supersymmetry breaking parameters induced by theScherk-Schwarz (SS) boundary condition in 5-dimensional orbifold field theoryin which the quark and lepton zero modes are quasi-localized at the orbifoldfixed points to generate the hierarchical Yukawa couplings. In such theories,the radion corresponds to a flavon to generate the flavor hierarchy and at thesame time plays the role of the messenger of supersymmetry breaking. As aconsequence, the resulting soft scalar masses and trilinear $A$-parameters ofmatter zero modes at the compactification scale are highly flavor-dependent,thereby can lead to dangerous flavor violations at low energy scales. Weanalyze in detail the low energy flavor violations in SS-dominatedsupersymmetry breaking scenario under the assumption that the compactificationscale is close to the grand unification scale and the 4-dimensional effectivetheory below the compactification scale is given by the minimal supersymmetricstandard model. Our analysis can be applied to any supersymmetry breakingmechanism giving a sizable $F$-component of the radion superfield, e.g. thehidden gaugino condensation model.Comment: revtex4, 22 pages, some numerical errors are corrected in phenomenological analysis, main conclusion does not chang