Flavor mixing in gluino coupling in supersymmetric grand unified model and proton decay

As a candidate of the elementary particle model exceeding the standard model, the model with supersymmetry (SUSY) is conceivable. Particularly the minimal SUSY standard model (MSSM) by changing the standard model most simply to SUSY and the minimal SU(5) SUSY GUT by embedding this straightforwardly in the SU(5) grand unified theory (GUT) are expected to be credible as they realize the unification of gauge coupling with good accuracy. One of the features of the MSSM is the breakdown of SUSY. In the study of this time, the mixing between generations in the gluino coupling in the minimal SU(5) SUSY GUT based on the minimal supergravity was numerically investigated. The results obtained were applied to the calculation of proton decay in the minimal SU(5) SUSY GUT. As to squark flavor mixing in MSSM, the parameters in the MSSM, the flavor mixing in gluino coupling, and the evaluation of squark mass matrix are explained. The application of the mixing between generations in gluino coupling to the calculation of proton decay in the SUSY GUT is reported. As the result, it became clear that the mixing between generations in gluino coupling was about the same size as Kobayashi-Masukawa matrix elements. It was shown sometimes the contribution of gluino dressing became larger than the contribution of wino dressing. (K.I.)