This thesis presents two analyses of semileptonic b ' sl+l' decays using Flavour Changing Neutral Currents (FCNCs) to test for the presence of new physics and lepton ï¬avour universality, and the equality of couplings for different leptons, which on the basis of experimental evidence is assumed to hold in the Standard Model, free from uncertainties as a result of knowledge of the hadronic matrix elements. It also includes the angular analysis of Lambda_b->Lambda mumu decay and the RK* measurement, both of which are first measurements, not yet performed by any other experiment. | Searching for New Physics in b a sa+aa Transitions at the LHCb Experiment by Luca Pescatore, Hardcover | Indigo Chapters