Signatures of Supersymmetry at B-Factories

We discuss CP asymmetries in $B^0$-meson decays and \BsBs mixing within the framework of the supersymmetric standard model (SSM). It is shown that \BdBd and \KK mixings could receive sizable new contributions through box diagrams mediated by the charginos and charged Higgs bosons. This implies that the CP-violating phase of the Cabibbo-Kobayashi-Maskawa matrix may have a value which is different from the one predicted by the standard model (SM). The value of the CP-violating phase affects the amounts of the CP asymmetries and \BsBs mixing. We examine predictions for these quantities in both the SSM and the SM, exploring the difference between the two models.Comment: 12 pages; To be published in the proceedings of the Yukawa International Seminar '9

Realistic model for SU(5) grand unification

A grand unified model based on SU(5) and supersymmetry is presented. Pairs of superfields belonging to 15 and 15* representations are newly introduced, while gauge coupling unification is satisfied. Improper mass relations in the minimal model between charged leptons and d-type quarks are corrected. Neutrinos have non-vanishing masses, with large angles for generation mixings of the leptons being compatible with the small angles of the quarks. Constraints from proton decay are relaxed. A new source for lepton number generation in the early universe is provided.Comment: 9 page