Study Of B→s Rare Decays In The Minimal Supersymmetric Standard Model

The minimal supersymmetric standard model (MSSM) is indeed the simplest and most interesting supersymmetric model. In this paper, we studied the rare radiative decay b →sγ and the semileptonic decay b→sl⁺ l^- in both the standard model (SM) and the MSSM. Prom the currently available data of the considered rare decays, stronger limits on the mass insertion parameters of the MSSM were obtained. We also calculated the new physics contributions to the branching ratios of B → KÏ€ and B b →Kη^' decays.In the first two chapters, we firstly gave an introduction for the historic developments and current status of the theoretical and experimental studies of B meson decay processes. We presented a brief review about the basics of the SM and the MSSM, discussed the success and the difficulties of the SM, as well as the mass insertion approximation appeared in the MSSM. In chapter 3, we made a discussion for the effective Hamiltonian which govern the decay processes of B meson, the derivation and their renormalization group evolution of the Wilson coefficients, and collected all formulas needed in our calculation.Our own works are included in chapter 4 and 5. The major results are the following:(1) The information from the measured branching ratio of B → X_sl⁺l^- decay can helpus to improve the upper bounds on the mass insertions parameters Some regions allowed by the data of Br(B →X_sγ) are excluded by the requirement of a SM-like Cτγ(m_b) imposed by the data of Br(B →X_sl⁺l^-).(2) By using the QCD factorization approach, we calculated the new physics contributions to the branching ratios of eight two-body charmless decays: B → KÏ€, Kη^' After the inclusion of new physics corrections in the MSSM, the agreement between theoretical predictions and the measured values are improved.A short summary and some remarks are also given in last chapter.