CP asymmetry in $\overrightarrow{B}\phi K_S$ 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 $\overrightarrow{B}\phi K_S$ decay. After considering the constraints from $\overrightarrow{B}J/\psi K_S$ decay, we study three special scenarios: (a) large mixing between left-handed charm and top squarks, (b) large mixing between right-handed charm and top squarks, (c) large mixing between both left-handed charm-top squarks and right-handed charm-top squarks. We show quantitatively that because of large squark mixing within the second and third generations, an $O\left(1\right)\mathrm{}$ effect on CP violation in $\overrightarrow{B}\phi K_S$ is possible.

• Received 30 September 2003

DOI:https://doi.org/10.1103/PhysRevD.69.054001