Rare Semileptonic B Decays

In chapter 1 we introduce the general framework which we will adopt in order to deal with b -> s l+l- transitions. We explain the concept of effective hamiltonian presenting the SM operator basis on its possible extensions. After a short introduction to the theory of CP violation in meson decays we describe all the relevant observables that will be the object of our analysis. Chapter 2 is a technical introduction to the inclusive and exclusive decays B -> (X8 , K, K*) l+l-. In chapter 3 we present a model independent analysis (based on Ref. [6]) of the previoulsy described transitions focusing particularly on the CP asymmetries. In chapter 4 we discuss the structure of the MSSM and present our analysis of the supersymmetric contributions to the ·wilson coefficients (based on Ref. [7]). In chapter 5 we present the analysis of the impact of supersymmetry on the relevant observables (based on Refs. [7, 8]).