Comparative study of CP asymmetries in supersymmetric models Original Research Article

We systematically analyze the supersymmetric contributions to the mixing CP asymmetries and branching ratios of image and image processes. We consider both gluino and chargino exchanges in a model independent way by using the mass insertion approximation method. While we adopt the QCD factorization approach for evaluating the corresponding hadronic matrix elements, a critical comparison with predictions in naive factorization one is also provided. We find that pure chargino contributions cannot accommodate the current experimental results on CP asymmetries, mainly due to image constraints. We show that charged Higgs contributions can relax these constraints making chargino responsible for large asymmetries. On the other hand, pure gluino exchanges can easily saturate both the constraints on image and image CP asymmetries. Moreover, we also find that the simultaneous contributions from gluino and chargino exchanges could easily account for the present experimental results on the mentioned asymmetries. Remarkably, large experimentally allowed enhancements of image branching ratio can easily be achieved by the contribution of two mass insertions in gluino exchanges. Finally, we analyze the correlations between the CP asymmetries of these processes and the direct CP asymmetry in image decay. When all experimental constraints are satisfied, supersymmetry favors large and positive values of image asymmetry.