CP Asymmetries of B → φKS and B → η′KS in SUSY GUT Model with Non-Universal Sfermion Masses

We analyze CP asymmetries of B -> phi K-S and B -> eta ' K-S in a supersymmetric grand unified theory in which only the third generation sfermions contained in 10(Q,U-c,E-c) of SU(5) can have a different mass from the others. One of the advantages of this nonuniversal mass model is that the first two generation sfermion masses can be large whereas both (left arid right handed) stops are light so as to stabilize the weak scale. Therefore, we studied a minimal supersymetric standard model parameter region in which a fine tuning in Higgs sector is relaxed owing to light masses of stops, gluino arid higgsinos. In such a parameter region, the chargino contribution is is important as the gluino one. We show that the CP asymmetries of B -> phi K-S and B -> eta ' K-S can deviate from their standard model predicted values by O(0.1) because of constructive interference between gluino and chargino contributions.