Flavor changing neutral current processes in B and K decays in the supergravity model

Flavor changing neutral current processes such as (Formula presented) (Formula presented) (Formula presented) (Formula presented) (Formula presented) (Formula presented) and (Formula presented) are calculated in the supersymmetric standard model based on supergravity. We consider two assumptions for the soft supersymmetry breaking terms. In the minimal case soft breaking terms for all scalar fields are taken to be universal at the GUT scale, whereas those terms are different for the squark-slepton sector and the Higgs sector in the nonminimal case. In the calculation we have taken into account the next-to-leading order QCD correction to the (Formula presented) branching ratio, the results from the CERN LEP II superparticles search, and the condition of the radiative electroweak symmetry breaking. We show that (Formula presented) and (Formula presented) can be enhanced up to 40% compared to the standard model values in the nonminimal case. In the same parameter region the (Formula presented) (Formula presented) and (Formula presented) branching ratios are reduced up to 10%. The corresponding deviation in the minimal case is 20% for (Formula presented) and (Formula presented) and within 3% for (Formula presented) (Formula presented) and (Formula presented) For the (Formula presented) process a significant deviation from the standard model is realized only when the (Formula presented) amplitude has an opposite sign to the standard model prediction. The significance of these results from possible future improvements of the (Formula presented) branching ratio measurement and top squark search is discussed.