This thesis presents two analyses performed within the LHCb experiment, studying the decays of KS → π+π−e+e− and Λ0b→ Λγ. Firstly, a preliminary analysis is presented focusing on a rare decay of strange mesons, KS → π+π−e+e−. Secondly, the main focus of this thesis is presented in the form of the angular analysis of the Λ0b→ Λγ decay mode. Which allows to perform the first measurement of the photon polarization of b→ sγ transitions in radiative b-baryon decays. These studies are performed using data collected during Run 2 by the LHCb experiment at CERN, at a center of mass energy of 13TeV