Chargino contributions to the CP asymmetry in B→φKS decay -: art. no. 095004

We perform a model independent analysis of the chargino contributions to the CP asymmetry in the B-->phiK(S) process. We use the mass insertion approximation method generalized by including the possibility of a light right stop. We find that the dominant effect is given by the contributions of the mass insertions (delta(LL)(u))(32) and (delta(RL)(u))(32) to the Wilson coefficient of the chromomagnetic operator. By considering both these contributions simultaneously, the CP asymmetry in the B-->phiK(S) process is significantly reduced, and negative values, which are within the 1sigma experimental range and satisfy the b-->sgamma constraints, can be obtained.