[Formula presented] mixing in supergravity models

We consider the supersymmetric contributions to [Formula presented] mixing in the supergravity (SUGRA) models, which arise from box diagrams where charginos and up-type squarks or charged Higgs bosons and up-type quarks are exchanged. We have calculated [Formula presented], which is defined to be the ratio between the minimal supersymmetric standard model (MSSM) contributions to [Formula presented] and the standard model one. By choosing a particular set of Cabibbo-Kobayashi-Maskawa parameters allowed by the present data along with the present experimental data on [Formula presented] and [Formula presented], which lead to [Formula presented] in the MSSM, we have demonstrated an indication of possible constraints on [Formula presented] and [Formula presented] in the SUGRA models. As a result, for [Formula presented] GeV and [Formula presented], we obtain [Formula presented] GeV for [Formula presented] in the no-scale SU(5)×U(1) SUGRA model and [Formula presented] GeV for [Formula presented] in the dilaton SU(5)×U(1) SUGRA model. In the minimal SU(5) SUGRA model, however, we find no constraint from [Formula presented]. It will be very interesting for one to see what values for [Formula presented] the future experimental data would prefer.