In this thesis the search for the decay Lambda(b) -> K- mu+ is presented using the Run I data of the LHCb experiment. The decay offers an approach to describe the matter antimatter asymmetry in our universe according to the Sakharov conditions that require the violation of the baryon and lepton number. In the underlying including about 50 billion Lambda(b) decays no signal events are
observed and an upper limit of 1.95x10E-9 on the branching ratio is determined at a
confidence level of 90%.