29 0 v 2 1 N ov 2 00 3 Chargino Contributions in B → φK S CP Asymmetry

CP asymmetry in B → φKS decay is studied in the special context of supersymmetry theories, in which the charginos play an important role. We find that in addition to the gluino, the chargino can also make large contributions to CP asymmetry in B → φKS decay. After considering the constraints from B → J/ψKS decay, we study three special scenarios: (a). Large mixing between left-handed charm and top squarks(LL mixing); (b). Large mixing between right-handed charm and top squarks (RR mixing); (c). Large mixing between both left-handed charm-top squark and right-handed charmtop squark(LL+RR mixing). We show quantitatively that because of large squark mixing within the second and third generations, an O(1) effect on CP violation in B → φKS is possible. PACS numbers: 13.25.Hw; 12.60.Jv; 11.30.Pb